A.C. Simpson, Gin Manufacture, 1966

I thought this paper was so good and so useful I’d retype it so it could be better indexed by google and more easily found. I have one more bulletin of blockbuster importance to write about before I write my annotated bibliography of gin. Amidst the document, I may input my own comments as quotations via the WordPress formatting.

My aim with all these documents is to raise the quality of gin from new producers. Remember, a high tide lifts all boats.

A.C. Simpson, Gin Manufacture. Process Biotechnology, October 1966.

Gin Manufacture
A.C. Simpson, B.Sc. joined W.&A. Gilbey at Harlow, Essex in 1956 as research assistant. In 1961 he was appointed chief chemist with general responsibilities for quality control and wine and spirit bottling.

The key factors in the manufacture of gin are the spirit used, the botanical formulae and the technique of distillation. Unlike whisky, the spirit used for gin should have no indigenous flavour, the taste of the final beverage deriving entirely from the juniper, and other botanicals. The present article, dealing primarily with the manufacture of London dry gin, also points to the differences between this and gins such as Steinhager and Borovicka.

Most of the gin produced and drunk throughout the world is correctly described as London dry gin: the description relates to the process and not the siting of the distillery. Holland’s gin, centred in the town of Schiedam in the Netherlands, is distinct in flavour and method of production. Plymouth gin comes from a unique distillery in Devon. A large quantity of gin is also made, generally for limited local markets, by various compounding and flavouring techniques. It is the manufacture of London dry gin which is specifically described in this article.

The word ‘gin’ is derived from the French ‘geniève’, meaning juniper: it is from this plant that the principal flavouring agent is drawn. Gin is said to have been invented by the Dutchman, Franciscus de la Boe in the seventeenth century, as a specific based on the diuretic properties of juniper oil [1 Encyclopedia Britannica]. Despite a medicinal origin, gin had acquired a reputation in England a century later which was the contrary in extreme. It had become the principal agent of drunkenness among the lower classes and notorious gin shops of the period displayed such enticements as ‘Drunk for 1d, dead drunk for 2d, straw for nothing’. Improvement came about with the retail licensing system and eventual concentration of distillery practice into the hands of a few large companies which developed individual strictly secret formulae. Lately the production of gin has been subject to scientific control in order to maintain uniformity in an essentially batch process.

By definition London dry gin is made from a relatively pure ethyl alcohol, flavoured by redistillation with various plant materials (botanicals) notable for their richness in essential oils. In a classification of spirits, gin is first cousin to liqueur and only distantly related to whisky and brandy, in which the flavour derives from the source of the alcohol.

Compound gin, made by the direct addition of essential oils to the spirit is inferior in quality to distilled gin. The property of dryness in gin is associated with degree of flavour: a very dry gin is distilled from a low proportion o botanicals.

Gin is classified for Excise purposes as British compounded spirit which can be manufactured from immature spirit and distributed to the public without a statutory age.

All spirits are defined for Excise, general trade purposes and retail in terms of percentage of proof spirit, a scale of alcoholic strength linearly proportional to percent ethyl alcohol by volume in which proof spirit has a specific gravity of 0.92308 at 51°F [2]. On this scale, pure ethyl alcohol equals 175.35% proof; and 70% proof, the normal retail strength of spirits is equivalent to 40% by volume at normal temperature. In the parlance of the trade the former strength is 75 op (over proof) and the latter 30 up (under proof).

Gin production demands a supply of rectified fermentation spirit. The spirit much be clean and neutral in taste and odour and contain only traces of aldehydes, esters, fusel oils and other congenerics. The carbohydrate source of the spirit is generally grain (maize) but gin can be made from spirit of any source if it conforms to high analytical standards and is free from contaminant or congeneric odours. Spirit from molasses and, possibly, potato may therefore qualify (in Russia, spirit for vodka comes from these substrates). As the initial production of spirit is not an essential part of gin manufacture many gin distillers are not, themselves, producers of spirit.

This last paragraph is interesting because now there is the emerging idea that you can only be a “craft” distillery if you produce your own neutral spirits even if you probably shouldn’t create the environmental burden.

The basic spirit is made from grain by saccharification of the mash with malted barley and distillation of the fermented mash in a patent still. The methods and materials bear a close relationship with those of the grain whisky industry. A spirit suitable for gin is obtained from Scotch grain whisky by re-rectification.

I wonder what percentage of patent still whiskey production in Scotland is shipped to gin producers. Negligible or greater than 10%?

For the production of alcohol of good organoleptic quality from a fermentation spirit the fusel oils should be removed at the appropriate plate in the rectification column. Neutral alcohol is collected at the highest possible proof.

In North America, grain alcohol of extremely high purity and odour quality is produced in distilleries operating continuous, multi-column stills. Strict attention is paid to the conditions of fermentation, both in temperature control and sterility: the object is to maximize the yield of ethyl alcohol from a given weight of grain. The composition of the mash is regulated to secure good enzymatic conversion without the formation of much fusel oil. The spirit produced is adequate in quality for either gin or vodka manufacture. Some grain spirit made in Britain for gin retains an odour suggestive of its origin, due to incomplete rectification and purification. Many gin distillers who are not spirit manufactures rectify the spirit they buy before distilling it into gin.

It surprised me that they rectified. You’d think as far as energy usage went, it would make more sense to get it done to spec the first time, but maybe the industry was not that organized yet. I think the above paragraph is a shout out to Seagram’s.

The essential botanical of gin is the berry of the European juniper tree, Juniperus communis L; other flavouring agents come from a number of plants including coriander, angelica, orange, cinnamon, nutmeg, cardamom, orris and others. Juniper berries, coriander seeds and angelica root are probably common factors in the composition of all London dry gins but the proportions differ from one distiller to another. The ratio of the three main flavouring agents and the inclusion of other selected botanicals are defined by the distiller’s formula: an original combination which determines the character of gin. Distillers therefore do not disclose their botanical formulae.

Juniper berries [6] for the purposes of gin distillation are grown in Central Europe; the best berries come from the Chianti district of Tuscany but suitable material is also obtainable from Southern Germany and Yugoslavia. Berries from the Tyrol, Hungery and Czechoslavakia are generally utilised for local production of a juniper liqueur. At maturity the berries are smooth skinned, deep blue in colour and 5-8mm diam. Fruiting is biennial and the ripe berries are removed by harvesters who agitate the branches of the trees causing the berries to fall upon sheets laid on the ground. The berries are winnowed and carefully dried avoiding damage and fermentation, and sorted into culinary and industrial grades. The adulteration of berries with those of other species of Juniperus, e.g. oxycedrus is no longer so widespread because collection of the adulterant is no less arduous.

Gin I imagine demands the culinary grade of juniper?

Juniper berries are classified and selected for gin on the basis of appearance and the physical and organoleptic properties of the extracted essential oil (1.5-3.0%). Several components of the oil have been isolated and identified [6-8], by gas chromatographic analysis, Klein and Farrow [9] found 26.5% ∝-pinene, 9.0% myrcene, 8.8% sabinene and 3.8% limonene. It is to be expected that the components and the flavour of the oil will vary with locality and season: these factors are reflected in the physical properties of the oil on which the criteria of selection are based. For gin the berries should not give an oil with a predominantly terpenic odour [10]; the oxygenated compounds, in particular terpinen-4-ol, possess the aromatic flavour which characterises the best berries.

The criticism here of terpenic odor I think is why non communis Junipers are discouraged.

The second major botanical, the fruit of the herbaceous annual Coriandrum sativum [4], is cultivated in Russia, Roumania and other East European countries, for the supply of gin distilleries and the essential oil industry. The crop is also grown in the US, North Africa and surprisingly, in Essex, whence it is available to the English distiller after a good summer. Harvesting coriander demands judgement, for the fruit ripens sequentially and the farmer risks on the one hand an immature crop, and, on the other, shattered fruit with excessive loss of oil. It has been found that the crop contains the highest proportion of usable seed and quality of oil when the fruit on the central and first order umbels turns a chestnut colour [11]. The dried seeds (fruit) and 2-4 mm diam., number 100-130 to the gram and possess a perfumed but slightly cloying odour. Russian and English coriander seed yield 0.8-1.2% and 0.3-0.8% oil on steam distillation. As in the case of juniper berries, coriander seed is selected for gin on the physical properties of the distilled oil and organoleptic quality in dilute alcoholic solution. The main component of the oil is d-linalool (60-70%); other oxygenated compounds, geraniol, l-borneol and n-decanal are present [4].  Monoterpenic hydrocarbons occur (10-20%), principally as γ-terpinene, d-limonen and ∝-pinene [12].

The dried root of Angelica officinalis (Hoffm) provides a third important gin botanical [4]. The plant is cultivated in the temperate climate of Europe and the distiller’s requirement is met with the produce of an entirely cottage industry in the East German provinces of Thuringa and Saxony. The roots are plaited and hung up to dry: during storage changes occur in the yield and properties of the oil which becomes darker in colour, higher in specific gravity and lower in optical rotation and acquires a musk-like odour due to the predominance of high boiling lactones.

I’ve definitely over looked Angelica, but he’s totally got me with musk-like and high boiling lactones. Does it conform to anyone else’s experiences? A nice thing about Simpson is that he dares use sensory descriptors.

Other ingredients in gin formulae vary with distillery practice and are generally included in lower proportions, often only a few ounces in a charge of several hundred pounds. Common minor ingredients are: sweet orange peel (Citrus sinensis L.); bitter orange peel (Citrus aurantium L.); lemon peel (Citrus limon L.); cinnamon bark (Cinnamomum zeylanicum Nees); cassia bark (Cinnamomum cassia Nees); cardamom seeds (Elettaria cardamomum Maton); nutmeg (Myristica fragrans Houtt); orris root (Iris pallida Lam); and liquorice root (Glycyrrhiza spp.).

A few ounces to several hundred pounds is a big claim. I know a lot of new producers are trying to push supporting botanicals forward in search of distinction and perhaps they shouldn’t. Some of these material are particularly high in oil contents and perhaps have unique thresholds of detection so the addition may be far more than symbolic.

Small quantities of these botanicals may have a considerable effect on the flavour of the gin, being rich in oils of highly odorous composition. Orange oil [3] is 90% d-limonene and cinnamon bark and cassia bark oils [4] contain 60-70% and 70-95% cinnamic aldehyde. Other gin botanicals have been reported; aniseed, caraway seed, fennel seed, calamus root, geranium leaves, grains of paradise, turpentine and cubeb berries [13,14].

Many of the botanical ingredients described lose important quantitative and qualitative fractions of their oil on storage. Juniper berries stored a year for gin suffer a reduction of 20% in oil content and between 15 and 30% in moisture [10]. Coriander seeds lose absolutely 0.18-1.5% oil on prolonged storage at -14°C and 30% total oil in a year when stored in large hermetically sealed containers [15]. Citrus oils undergo autocatalytic oxidation when the peel is exposed to light and moisture [3]. Decorticated cardamom seeds lose 30% oil in eight months [5]. Stored botanicals are liable to insect infestation. Careful storage of botanicals by the distiller is necessary if he is to produce a consistently flavoured gin or avoid the evaporation of his flavouring material into the atmosphere. Ideally the botanicals are stored under temperature and humidity controlled conditions.

The botanicals are proportioned according to formula and loaded into the still. A specified quantity of spirit, reduced to a strength of 80-100% proof is added (the exact strength depends on individual practice) and gin is collected as a definite fraction of the distillate. In Britain, gin distilleries and rectifying premises are not bonded but the still are secured by Excise lock and distillation of a set volumetric charge only is permitted. In North America, gin distilleries can be operated under bond.

The comment “the exact strength depends on individual practice” may conform to my idea that percentage alcohol in the still governs time under heat and that too low an alcohol content uses excessive time under heat (heating water you don’t need) while too high risks boiling the still dry.

The shape and design of the gin still and the manner of distillation constitute the third important factor in the manufacture of gin. The dimensions of the still relative to the volume and strength of the charge, the supply of steam to the jacket and cooling water to the head, determine the reflux ratio and hence the composition of the distillate. For a still of given reflux ratio and charge of specific composition the distiller modifies the production by selection of the middle cut of the distillate and also sometimes by a second distillation. Gin stills are built to exacting specifications by experts; and vary in capacity from a few hundred to several thousand gallons, measured to the level of the man-door in the pot of the still. The construction is always in copper and usually in the form of a simple pot still with tapering head which curves at the highest point into the downward sloping lyne arm (Fig. 1). The head may be expanded into a bulbous shape immediately above the pot. In some distilleries still heads are equipped with water jackets through which cold water is circulated during distillation; at another distillery a system of return flow conducts a preliminary condensate of higher boiling volatiles back to the pot of the still. All these features promote reflux in the course of distillation. The distillate is conveyed through a tubular condensor and is piped to inspection chambers for continuous measurement of alcoholic strength by means of in-line hydrometers; thence it passes to collection vessels. Stills are heated with steam generally applied to the jacketed base but some stills function with internal steam coils. Gauges for steam pressure, temperature of the liquid contents of the still, temperature of the distillate vapour and the condenser water are centralised in the modern distillery in a control panel.

The still head jacketed with water is sometimes called a “brandy ball” and is a method of providing optional degrees of reflux.

In operation the still is brought to boiling and the first few gallons of distillate rejected; this fraction is termed heads. Collection point for the middle cut of the distillate may be determined by an arbitrary quantity of heads, by the temperature in the column or by the appearance of the distillate. As the still charge is depleted of alcohol and steam pressure is raised to maintain distillation rate and when strength of the distillate falls to a predetermined value the still is struck and the distillate diverted into the second collection vessel. The still much now be exhausted of alcohol (tails) before the residue may be discharged. Combined heads and tails are called feints. The middle fraction of the distillate is gin, with a mean strength of 30-50 op. Still residues may be discharged to sewer after sedimentation and appropriate treatment. Feints are rectified in a special still with high reflux ration and the recovered spirit is added in constant proportion to the gin still charge. Feints may also be cleaned up by treatment with charcoal or potassium permanganate.

“by appearance” I think implies a demisting test where a sample is quickly taken and diluted to observe the degree of louching. This is correlated to how far has progressed and can probably be performed quickly enough to make a useful decision. The decision is gin product is of elevated importance because fractions are not recycled like other spirits. When the feints are recycled, they are stripped to neutral.

Alternative systems of distillation are sometimes adopted. In one variation the botanicals are place in a mesh tray above the liquid surface in the still. Volatile oils are extracted by heat and by contract with refluxing liquid but the botanicals so not undergo the maceration which occurs in the action of boiling. Some gin stills have been operated under reduced pressure.

What I haven’t figured out yet, is whether only the largest stills used gin baskets (my theory) because their time under heat was so long it compared to botanicals being boiled in a smaller still. Seagram’s early on was experimenting with partial vacuum.

In order to equalise the slight differences which result in the product of successive distillations in spite of the applications of rigorous quality control methods, gin should be blended in large holding tanks before transference to the bottling warehouse. Gin is diluted with distilled or demineralised water to bottling strength which in Britain is generally 70% proof. Water, free of dissolved solids, is used because otherwise the calcium and magnesium salts of hard ware are precipitated, giving sediments and chalky incrustations in the bottles [16]. Gin is colourless liquid and is often marketed in clear glass bottles. In order to attain the clarity demanded, gin is filtered (polished) before bottling, usually with cellulose-asbestos sheets in plate and frame or where throughput is large, with a filter-aid such as kieselguhr. Gin requires no period of laying down or maturation for improvement. The flavour derives entirely from the essential oils of the botanicals which are present in the condensate of the still. With gin the maxim might be ‘the earlier drunk the better’, for essential oils in dilute solutions tend to oxidise slowly with a detrimental effect on the flavour of the gin.

I think filtration and “polishing” are more important than some would think. I used to think polishing was only for dust and dirt but I think freshly distilled gin with always have errant out of solution terpenes that are some how emulsified and prevented from floating to the top. I’ve had big successes polishing very cloudy gins with sand (and there are lots of ins and outs of that), but the kieselguhr (diatomaceous earth) idea was new to me and I still do not exactly understand how it is applied. Stirred to attract particles then collected by the filter?

Analysis and quality control
The difference in flavour between well known brands of gin is distinctive even to the untutored palate. In order to maintain the distinction the distiller seeks to reproduce from one distillation to the next and from one year to another, a gin which is uniform in flavour. This is the aim of all producer of blended and compounded spirits but in the case of gin the process is more amenable to control. The whisky blender chooses from a wide range of finished whiskies, where as the gin distiller selects his raw materials and adapts his process to suit them. In the past, distillery organisation was based exclusively on the distiller’s palate and practical experience: today laboratory analysis and panel tasting play an important part.

I’m wondering if when Simpson says “where as the gin distiller selects his raw materials and adapts his process to suit them” he pretty much refers to scaling the botanical charge and blending stocks of botanicals to average out oil yields and their sensory properties. I suspect that the cut points stay as definite as possible batch to batch and the charges are reconfigured from different lots of botanicals to fit. And what of these master distiller’s? Do decisions at Tanqueray get made by the sole experience of a Tom Nichol or does he crunch numbers on the tasting panel, consult the analysis and paint by numbers? He did say recently that I make things too complicated. How far into the future are the international brands from the techniques laid out in this document?

The factors which determine the flavour in a bottle of gin have been described: spirit, botanical formula and technique of distillation. The distillation is a matter of control on the spot, with the still operator making adjustments in steam pressure and water flow from observations of the strength and rate of flow of the distillate. Modern distilleries utilise automatic steam valves, flow meters and other mechanical devices to obtain a precise control and the time of the entirely automated gin distillery approaches.

Did we ever get there? And if so, how small does it scale?

Botanicals and spirit were in the past selected wholly on the organoleptic evidence and while this method remains paramount in importance, it is necessarily supplemented by laboratory analysis. Control by tasting in the food industry has undergone a major rethinking in the last 10-15 years and the new methods are finding their way into traditionalist strongholds. In the US the standardisation of quality in distilleries through the use of taste panels numbering 20-30 persons is a widely employed technique [17]. Panelists are members of the distillery staff selected by test and they examine apparently similar samples daily in difference tests of the triangular or duo-trio type. Differences between the samples examined are expressed in statistical terms. Gin is amenable to this method of organoleptic examination because the accepted standard sample, properly stored, remains in good representative condition for a number of weeks. Panel tasting can be applied to finished gins as a test of uniformity, to spirit to check that it is up to standard and to dilute alcoholic solution of essential oils extracted from botanicals.

I was at a coffee roaster recently, Blue Bottle, and they were setting up panels for their quality control and every staff member knew how to quickly participate. I’ve tried to explain the importance to a few small distilleries and they just weren’t there yet.

Analysis of spirit has been restricted mainly to chemical methods: esters (expressed as ethyl acetate) by direct saponification; aldehydes (as acetaldehyde) using Schiff’s reagent; and fusel oil by the Komarowsky reaction. These methods give acceptable, meaningful results at intermediate and high levels of congenerics but approach the limit of accuracy when applied to the highly rectified spirits required for gin. It has been reported that the ‘fusel oil value’ of rectified spirits measured by the Komarowsky reaction is not necessarily an accurate measure of higher alcohol content but is a useful index of spirit quality [18]. Another widely used empirical measure of spirit quality is the permangranate time test which estimates the content of reducing substances by the rapidity with which a standard solution of potassium permangranite in contact with the spirit is decolorised. Ultra-violet spectrophotometry has been applied with some success to spirit analysis and provides a rapid instrumental assessment of inherent quality [19]. In Table 1 an analysis of an number of spirits used or proposed for use in gin distillation is presented together with a ranking of organoleptic quality by a small taste panel.

This all concerns the neutrality of the base spirit which is less of an issue now because it can be purchased from exacting specifications.

In the examination of gin botanicals for purchase or at intervals in storage, only juniper, coriander and angelica are likely to be subjected to a detailed laboratory analysis. The other botanicals would be distilled on pilot scale both individually and as ingredients in the formula and compared by taste against accepted standard. The essential oil of juniper berries, coriander seeds and angelica root are isolated from the plant material by steam distillation [20] and are measured volumetrically and for refractive index. The range of refractive index of the oil of juniper berries suitable for gin has been reported as 1.4840-1.4870 [10]. Lower values are indicative of a high content of low boiling terpenes which is undesirable in gin. Coriander and angelica oils should show refractive indices between 1.463-1.471 and 1.476-1.488 [4]. Ultra-violet absorption provides a rapid and valuable check of oil composition; juniper oil absorbs strongly in the region 220-240 mμ which is coincident in wavelength with a plateau in the absorption spectrum of terpinen-4-ol, and important constituent. Dilutions of juniper oil in 70° proof alcohol demonstrate an obedience of Beer’s Law at 225 mμ. Coriander oil begins to absorb at wavelengths less than 220 mμ but useful data are obtained if stray light factors are considered. Dilutions of the oil in alcohol are check by taste against standard samples. Moisture content of botanicals is determined by Dean and Starke tube.

New to me was that only the most significant botanicals were analyzed for oil yield and refractive index. I’ve slowly been doing a lot of work on the techniques and just found the block buster document on the subject from the horse’s mouth. Insignificant botanicals still get essayed but in an abbreviated form. I remember years ago tasting single botanical distillates from Citadelle, and each was startlingly beautiful with amazing focus and clarity of aroma. I thought that maybe they were prepared specially for the presentation, but they made have just been routine distillations performed for every batch of new botanicals.

Analysis of gin botanicals enables the distiller to base flavouring formula of his gin upon the definite properties of the batch in current use. Lots of berries or seeds with high and low oil contents may be blended together to give an appropriate intermediate level and a new season’s crop rich in oil can be phased into production with the least disturbance of the flavour characteristics of the gin. Purchase of botanicals each year from a range of samples supplied by the broker is made selectively on the basis of oil and moisture content, and composition and flavour of the oil in comparison with current stocks.

The finished gin is too dilute in oil to allow chemical analysis but control by tasting is supplemented by measurements of ultra-violet absorption. No published work exists on the application of gas chromatography to gin analysis but even with the most sensitive equipment, some preparation and extraction of sample is anticipated.

Other gins
Holland’s gin possesses a heavy, full-bodied flavour which derives not from the botanicals used in the gin distillation but from the original spirit; the gin character comes essentially from juniper berries but is overlaid with whisky-like congenerics. A mash containing up to 30% malt is fermented and distilled in a pot still with low rectification. The distillation may be repeated several times but the final spirit (moutwijn) does not show the neutral characteristics demanded for London dry gin. Originally the botanicals were added to the fermented mash before distillation.

Steinhager (Germany and Austria) or Borovicka (Hungary) is the distilled product of crushed fermented juniper berries [21]. It is twice distilled to a final alcohol strength of 70-85% proof. The stillage is and important source of oil of juniper.

Old Tom is a gin sweetened after distillation of approximately 3% w/v sugar. It is uncommon now in the English market but is still exported. Sloe gins, lemon and orange flavoured gins are made by steeping finished gin in the fruit or peel.

Thanks are due to the directors of W.&A. Gilbey Ltd for permission to publish this article; to Mr. M.S. Aldridge, distiller for his co-operation and Messrs M.G. Farey and C.C.H. Macpherson for analytical work.

1. Encyclopedia Britannica, 1964
2. Customs and Excise Act, 1952, Section 172(5).
3. Guenther, E. ‘The Essential Oils’, Vol. III (1949), D. Van Nostrand Inc. New York.
4. ——, Ibid., Vol. IV (1950), D. Van Nostrand Inc. New York.
5. ——, Ibid., Vol. V (1952), D. Van Nostrand Inc. New York.
6. ——, Ibid., Vol. VI (1952), D. Van Nostrand Inc. New York.
7. Motl, O., et al. Chem. Listy (1956), 50, 1282.
8. Hirose, Y., et al., Nippon Kagaku Zasshi (Japan) (1960), 81, 1776.
9. Klein, E. and Farrow, H. Dracogo Rept. (1964) 11, (10), 223.
10. Willkie, A.F et al. Ind. Eng. Chem. (1937), 29, 78.
11. Chikalov, P.M. Maslob-Zhir. Prom. (1962), 28 (2), 26.
12. Ibeda, R.M., et al., J. Food Sci. (1962), 27, 455.
13. Levin, H.J., Am Wine Liquor J. (1940), 7, 26, 33.
14. Jacobs, M.B., Am Essent. Oil Rev. (1949), 53, 54.
15. Rabora, N.V., Spiritovaya Prom. (1961), 27 (5), 13.
16. Warwicker, L.A., J. Sci. Food Agric. (1963), 14, 371.
17. Brandt, D.S., Lab. Pract. (1964), 12, 717.
18. Berganger, E., and Babel, W., Nahrung (1964), 8, 192.
19. Merke, R., et al., Branntweinwirtschaft (1960), 100, 479.
20. Clevenger, J.F., J. Amer. Pharm Assoc. (1928) 17, 345.
21. Stucklik, V., Sbornik Ceskoslov. Akad. Zeinedelske (1950), 22, 363.

Process Biochemistry, October 1966

Rare Vantage: Beverage History From The Spirits Chemist

I recently acquired another forgotten gin document, titled The History of Gin, by the chemist, D.W. Clutton, who gave us some of the most important works on gin distillation and chemical analysis. But what would such an important chemist speaking in 1972 have us know about gin? Read it and find out.

Clutton also wrote a wonderful history of rum that is notable and well organized. There are brilliant snippets and descriptions plus a bibliography of forgotten articles not seen elsewhere (that of course I’m already tracking down).

I also just digitized my copy of Herman Willkie’s Beverage Spirits in America —A Brief History (I apologize, but you will have to rotate the view of the PDF once you open it). This was an adaptation of Willkie’s 1947 address to the Newcomb society. It also answers the question: what would the greatest distiller of the 20th century have us know about American beverage history? And he goes on to say a great deal of things that were new to me. Some parts are so wonderful I dare not spoil them for you.

Clutton’s history of gin is really interesting and I’ll highlight what caught my eye. The most interesting parts are centered around Plymouth Gin and Old Tom.

J.B. Priestly described Plymouth gin as the gin ‘with a suggestion of a fresh morning at sea about it’.

The production of Plymouth gin is very localized. Messrs. Coates & Co. (Plymouth) Ltd. are the sole agents for its manufacture (with the exception of New Zealand, Germany, and Italy, where it is produced under license).

This was new to me and surprising as lately they hype their appellation status. More spirits are licensed for production in multiple locations than you’d think.

The secret of the success of Plymouth gin derives from the soft pure water which runs from the river Meavy, through the granite of Dartmoor. Spirit is obtained from grain whisky distilleries in Strathclyde, or occasionally from a London grain spirit supplier.

I began to wonder why he goes into such detail. Either Clutton was an employee or they just hosted him. It seems like Plymouth existed in a world where gin was simply a commodity but as often as possible they tried to elevate it to something fine.

During the war, molasses spirit had to be used, much to the disgust of the manufacturers. Eventually, however, the switch was made back to grain spirit, and this was commemorated by the following telegram sent from Glasgow—

From the land of Scotch and Bonnie Lasses,
We’re glad you’ve given up molasses
and Plymouth gin is once again,
The very best and made from grain.

The grain spirit is pumped into the still and reduced with the famous water to ca. 25° over proof and the spirit is rectified. The spirit is then pumped into a pot still and the botanicals are added. The centre portion of the distillation is reduced in strength, taken into bond and bottled as Plymouth gin. ‘Plym-Gin’, as it is affectionately called, is exported to 80 overseas markets.

The term ‘dry’, as applied to London dry gin, means that the over-all flavour content is low. This arises since the gin is distilled from extremely pure spirit and a low proportion of botanical ingredients.

I interpret “low” here as low enough to be crystal clear. If the gin is cloudy from insoluble terpenes, it either has too much flavour and/or is cut improperly. I’ve been exploring a new technique for post distillation clarification of cloudy gins and I’ve having spectacular success. It will be the defacto practice once I write it up.

Another explanation [of Old Tom gin’s origin] of the term was given by Boord’s (Distillers) Ltd. of London (Est. 1726) They established that Old Tom referred to Old Thomas Chamberlain of Hodges Distillery. He was an experimenter in gin flavourings, and once added sugar syrup to London gin. One of Boord’s ancient labels showed a picture of ‘Old Tom’ Chamberlain.

Old Tom is a gin sweetened, after distillation, to 3 to 6% w/v of sugar (or occasionally glycerine). Occasionally the sugar syrup is flavoured with orange flower water, and is known as capillaire. Old Tom is no longer popular in England, but is still exported.

This wonderful Difford’s Guide article gives even more background to the origins of Old Tom. I think its references mainly comes from a book titled Slang and its Analogs.

Clutton’s Rum had some spectacular passages I’ve love to quote, but I’m short on time.

New Look


Ron here. I’m a long-time friend, ex-resident of the Houghton Street Speakeasy and technical advisor for Stephen.

Hope you all enjoy the new look. It really highlights the wonderful content Stephen writes. It should be more mobile-friendly as well.

Just wanted to share an R&D project I was working on today. Some of you may have heard about Bitcoin, the internet protocol used to send and receive value.

Here we use a Raspberry Pi controller for connecting to the Bitcoin blockchain over the internet. The Pi is controlling a switch that is connected to an electronically actuated standard NPS valve.

Raspberry Pi running Bitcoin-core controlling an NPS valve.
Raspberry Pi running Bitcoin-core controlling an NPS valve.

When the Pi controller sees a bitcoin transaction to a specific wallet address, it will open the valve. This means that anyone sending bitcoin to that wallet will cause the controller to open the valve, and pour the beer!

Now we can connect the valve to a standard keg, and we’ve got an automatic beer-pouring keg powered by bitcoin! This is literally a home-brewed homebrew Internet-of-things.

A working prototype will be coming to a bitcoin startup in Boston.


Originating a Gin

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To produce a gin from scratch,
first we must invent the universe.

Originating a Gin.

A giant hole in spirits production literature is the distillation of gin and the reason may be that it is seen as less of an agricultural activity than other spirits like the production of brandy, whiskey, or rum which attracts agricultural scientists. What limited amount of literature that does exist on gin does not exactly teach one how to develop a gin from scratch, but rather only to maintain and continue the production of an existing gin. Originating a gin is complicated and requires a lot of expensive trial and error, but hopefully by framing the process, a shorter path to success can be taken.

Gin is essentially spirit redistilled with various botanicals, most importantly juniper and coriander. The spirit is typically grain neutral spirit, but that isn’t always the case these days with other spirits as extreme as tequila successfully being used. There are different styles of gin like London dry, Genever, and Old Tom. The differences between the styles is not as clear as you’d think. It may be common knowledge that Genever is made from malt spirit while London dry is made from grain neutral spirit, but it isn’t common knowledge how the botanicals formulas differ in style. Between the different styles, there is definitely a blurring of the lines of some facets and that is part of gin’s charm. It would not prove helpful to define any of the categories so instead we will explore the shaping of the facets.

One of the first things to note about gin production is that just like distillation of spirits from fermentations, making cuts is also spectacularly important to gin. When distilling fermentations, the cuts are to remove and recycle congeners that are ordinary or objectionable while capturing congeners that are extraordinary, defining of the source material, and contributing to complexity at limited quantities. Gin follows a lot of the same objectives with regards to removing an excess of what is ordinary while capturing what is extraordinary, but the chemical compounds are mostly all different. Knowing them by name specifically is not always helpful, but understanding them in general will help craft extraordinary gins using only organoleptic analysis.

A lot of aroma is created or augmented during gin distillation, so just like spirits produced from fermentations, the sensory properties of a gin are also impacted by time under heat. Heat augments many of the extraordinary compounds in the flavoring material and renders them ordinary. These chemical compounds are mostly all in the terpene family. While full flavored spirits from fermentations are distilled slowly, gin is distilled swiftly, but at a pace in line with what the condenser can handle and the condensing temperature should ideally not exceed 20°C.

If a spirit is condensed above 20°C, it is far more likely to contain copper salts that are considered objectionable and possible toxic at extremely high levels. Many countries monitor the copper content of distillates and sometimes use the metric as a trade barrier to prevent crude and cheaply produced distillates from entering the country. Many new stills are being built with stainless steel condensors to limit copper contamination.

To reduce time under heat, some gins are distilled at either partial vacuum or fuller levels of vacuum. As degree of vacuum increases, so too does expense because more specialized equipment is required. Vacuum distilling is seductive, but not always worth the effort until other options and methodologies have been fully explored. Many of the greatest gins in the world are produced at atmospheric pressure without any degree of vacuum to lower the temperature.

Many gins are developed on small scale pilot plant equipment and then migrate to larger scale stills, but not many people are aware of the ways still size effects the product. The main difference is that still size impacts time under heat. A still of larger capacity takes longer to heat up and longer for the spirits run. If the botanicals are boiled in spirits, they will encounter heat for both the duration of the pre-heating and the duration of the spirits run, therefore time under heat can multiply quickly when still capacity increases.

One way to reduce time under heat is to use a gin basket. When the botanicals are held in a container suspended above the pre-heating liquid, they are not subjected to heat until vapor starts evaporating which marks the beginning of the spirits run. A gin basket can therefore significantly cut down on time under heat. On a small still, to gain time under heat, to approximate a larger still, botanicals can be heated in spirits while held in sealed jars sous-vide.

Even if the sous-vide technique is not used for pilot plant production, it can be used to explore the properties of botanicals. Nth degree scenarios can be created to teach sensory assessment where exaggerated amounts of time under heat are created for a botanical which can be compared to lessor degrees to get a first hand, abstracted, organoleptic, look at differences.

Some producers steep botanicals in spirits, typically at 60% alcohol, before distillation, often overnight. In many cases these botanicals endure significant time under heat after steeping and make very fine gins. Any combination of techniques can be used to control heat and its effect on aroma creation in the still.

Keep in mind, the 60% alcohol figure is not selected because it is the optimal proof to extract flavor, it is selected for other economies. If the figure were lower, it would take more energy to execute the distillation run because you would be heating water you do not intend to distill and this would also result in undue time under heat. If the figure was higher, less energy would be expended, but there would be a risk of boiling the pot dry and scorching botanical matter on the bottom of the pot or damaging a heating element. As the figure is optimized, these considerations should be taken into account.

The most important class of chemical compounds related to gins are terpenes which unfortunately can seem dauntingly complex. Fortunately, just like esters, some are ordinary and ubiquitous, having an analog to the very short chained ester, ethyl acetate, and others are extraordinary, more singular to each particular botanical, and defining of its most salient traits. Ordinary terpenes often act like olfactory shadows and they have unique perceptual effects above certain thresholds. Gins can be made to show higher contrast between botanicals by removing ordinary terpenes to reveal and promote extraordinary terpenes. Articulate manipulation of terpenes, often aided by sophisticated analysis techniques well beyond the means most startup distilleries, is the secret of the big gin brands.

Terpenes are hard to give a primer on because they are so diverse. Besides often varying in functional groups, they also vary significantly in their carbon skeletons. Countless chemical analysis studies exist that give very detailed breakdowns of the chemical composition of gins and other spirits, but these are typically for finished gins and not comparative looks at specific isolated fractions of gins. Knowing all of the chemicals by name does not prove especially helpful to the gin distiller until they can be attached to specific fractions in the distillation run or other specific distillation parameters, so they will not be covered here.

Contrast enhancement through ordinary terpene removal can seem counter intuitive because removing flavor ends up promoting flavor. Removing terpenes is the rule of thumb for essential oil production for perfumers and processed food flavor formulators, but the literature is short on complete explanations. It is often cited that the usage rate of an essential oil decreases after terpene removal which implies some sort of olfactory shadowing effect or change in threshold of perception of some compounds after others are removed. This knowledge reinforces the importance of making cuts for gin production.

Some gins are compounded from essential oils instead of distilled with botanicals and historically these have been very cheap gins. There have been significant advances in essential oil production since compounded gins gained their reputation, but originally they might have differed from distilled gins by the essential oils seeing significant time under heat when steam distilled and not benefiting from the fractional distillation allowed by distilling ethanol with water. Historically, essentially oils also saw significant amounts of adulteration. Terpenes can be separated from essential oils so fractionation can occur, but how it can compare to the results of a distilled gin has not been systematically explored. New methods of essential oil production, like super critical CO2 extraction, have been developed that may create new possibilities for compounded or partially compounded gins of extraordinary sensory quality, but they will likely face hurdles in a market that prizes traditional processes.

In regards to equipment, gin distillers have the option of using either pot stills or batch column stills, but column stills are often the preferred apparatus to distill at a consistent proof to more predictably stratify and sort terpenes when making cuts. By varying reflux, and thus relative equilibrium, a column still can easily achieve different distillation proofs during the spirits run from a multitude of input proofs. The only option for a pot still to control distillation proof is via the input proof of the spirits. If various practice runs are made to measure the distilling proof, a pot still can often gain the utility of a column still for gin production.

Sophisticated chemical analysis helps large distilleries sculpt their products and determine which distillation proofs and which cut volumes to use. When creating a gin from scratch without chemical analysis, not much can be done besides systematically and widely exploring all options. This can be expensive and time consuming, but as more investment is made to do it, the gin formula will move closer to its full potential.

Before significant investment is made to explore various still operation parameters, the options for standardizing botanicals should be learned. Large production gins rely on spectacular standardization of their botanical charges for oil yield and without it they would be working in the dark. Botanicals cannot simply be weighed because of significant variances in oil yield. Even within a given botanical’s essential oil, there can be significant variance of composition that should be taken into account whenever possible.

The simplest form of measuring oil yield is with Clevenger apparatus steam distillation. The essential oils are distilled with steam, and because they are not soluble in water, they separate so they can be collected, measured, and further analysis performed like the examination of refractive index which can imply properties of their sub composition. Much better results can be gotten from Soxhlet extraction with organic solvents, but the specialized glassware and accessories become more expensive. The largest scale distilleries use essential oil extraction with organic solvents. They then further analyze the essential oils with spectroscopy and chromatography to get complete looks at sub composition. Gins have to be produced at very large scales for many advanced forms of analysis to be economically viable at all.

One thing that sophisticated chemical analysis allows is the distilling of gin concentrates. The idea of creating concentrates which get diluted with more neutral spirit is seductive to small distilleries, but they are often not aware what exactly allows it to be done accurately. Congeners are being caught when they come out of the still and distilling a normal scale botanical charge is like catching an underhand lob while distilling a concentrate is like catching a fast ball. What you are really trying to catch is that exact point where you switch from collecting the heads fraction to collecting the hearts fraction. The difficulty of making the cut goes up dramatically when distilling a concentrate and it simply cannot be done without a well standardized botanical charge and further analysis of fractions from the distilling run.

Improper cutting of terpenes results in cloudiness and most all gins should be able to be made crystal clear by proper cutting. Terpenes are far less soluble in water than alcohol and as the proof drops, solubility decreases. This is best illustrated by diluting Absinthe with water and watching it quickly louche a milky white as terpenes come out of solution. In absinthe, louching is regarded as a feature, while in gin it is widely considered a flaw. Under some special circumstances that are not widely explored or documented, some large production gins contain food safe surfactants like glycerol to keep terpenes in solution. These should not be employed as a solution to fix faulty gins, but explored as a means to push boundaries with new gin types once production is widely explored.

When developing a gin formula, competitor analysis can be performed on commercial gins to aid the process. Commercial gins can be redistilled, ideally under vacuum, and separated into multiple fractions for organoleptic analysis along side other gins distilled under the same parameters to create equivalent fractions. The collected fractions can be cut to drinking proof and be nosed comparatively, either against complete gins or against single botanical distillates to reveal small details. The first fractions, which are concentrated with the most volatile terpenes, can be watered to test their ability to louche. Without sophisticated analysis, these simple tests can help control consistency and inform development decisions, such as increasing or decreasing the size of the heads fraction against the properties of industry leaders. It is highly recommended to own and explore the usage of small scale laboratory testing glassware before a gin is ever scaled up to production on a commercial size still.

A big secret of the the leading mass market gins is their spectacular sourcing. They are produced at such a scale where it is economically viable to visit the site of every source and know all their options. Large distilleries also develop quality control procedures and analysis techniques specific to every botanical they use. Large supplies of botanicals are properly stored to hedge against shortfalls and often introduced to the botanical charge by Solera method to increase consistency. This level of involvement is not always possible for the small scale distiller, but even when recognizing these facts it is possible to make extraordinary gins on the small scale.

Small scale distillers need to do their best to understand their options within their production scale. Botanicals are not all created equal and as an agricultural crop will often show significant inconsistencies that should be caught and accounted for. Spirits marketing homogenizes juniper to simplify an understanding for consumers, but on a sensory level not all juniper is created equal. The properties of juniper differs significantly by latitude and proximity to coast line. As juniper is grown further north and closer to the sea, it often becomes relatively more arid and drier in aroma. Extremes of character are classically seen as flaws, but within the new spirits market, where terroir is prized and there is more room for acquired tastes and individuality, there is room for former flaws to become marketed as features. Multiple species of juniper exist, but with only Juniperous Communis classically being seen as fit for gin production. Alternative juniper species present opportunities for new gin possibilities, whether used fractionally or in total, but it should always be remembered that they face an uphill battle in the market and their exploration should only come after production is sufficiently explored so the potential of their unique character can be isolated and not confused with other variables.

Very basic ideas in olfactory category theory can inform the creation of a gin botanical formula. Gins typically contain so many botanicals as to touch upon a broad array of olfactory categories. Gins are dominated by botanicals, particularly juniper, that are categorized as converging with acidity (the olfactory-acid). Other botanicals, like citrus peels, converge with sweetness while some converge with bitterness and others with the chemical senses like piquancy. Coriander may be requisite to a gin formula because it converges with multiple categories thus becoming a cornerstone.

Many botanicals, inhabiting the same category, like juniper and angelica, tonally modify each other to create an overtone that aspires to be extraordinary. On the other hand, anise can often be perceived as occupying the same category as citrus peel, but instead of producing an overtone, the combined botanicals produce an interval with a pleasurable expansive sense of space. Almond often produces a similar sense of space in relation to other olfactory-sweet botanicals. Too few botanicals could result in a boring gin, which truly isn’t often the case, and too many botanicals can create something blurred without enough contrast enhancement to draw any interest.

There are not many rules, but there are many pitfalls and seductive traps to avoid. Keep in mind, for every botanical that is added, there should be enough time to adequately perform analysis on that botanical and widely explore its relationship to the formula. Botanical formulas are not created at random or by savants. The creative linkage of every botanical in the formula can articulately be described using ideas in olfactory category theory to justify and strengthen all relationships. With a solid understanding of creative linkage, botanical formulas can be created that fill market voids, put to use opportune sourcing, or simply realize personal aesthetic dreams.

Gin production holds a lot of secrets, luckily they all can be unlocked with systematic exploration. Exploration starts with small scale laboratory glassware to perform single botanical experiments as well as competitor analysis. It migrates to the pilot plant where time under heat needs to be considered and eventually moves to a full scale commercial still. Sophisticated chemical analysis helps when developing a gin, but does not provide any short cuts, rather it only helps production scale dramatically upwards. Standardization of botanical charges is paramount for any gin to be taken seriously. There are many seductive ideas in gin production like distilling under vacuum or distilling concentrates, but they are considered advanced and should only be explored after other options have been sufficiently understood. The making of cuts is critically important to a gin, perhaps even more so than other spirits. Sensory science explaining terpene perception, in the context of essential oils, is not well understood and any lack of documentation is best overcome by creating systematic first hand organoleptic experiences. Cloudiness is the biggest pitfall of the new gin distiller and it must always be remembered that the industry leaders produce crystal clear gins.


By now many people have read this, but the only comment I received was from Tom Nichol the distiller of Tanqueray and creator of Tanqueray Ten. I mention both products because where some distillers only maintain gins they’ve inherited, Tom Nichol created an original gin with Tanqueray Ten which is widely seen as the most extraordinary new gin of the past numerous decades. He said via a tweet, “Great piece of reading, but sometimes we can make things sound more difficult than they really are.”

What I suspect Tom objected to was my very progressive ideas on olfactory category theory which I feel are important to creating botanical formulas under market conditions many of us face today. My ideas come from the perfume industry and are hardly thought of as progressive there. I think of those ideas as solving problems that the global gins do not have. Tom is in the heavy weight class and probably competes with less than ten gins in his class, each striving only to be more classic than the next. Small scale gins, for example only those from New England, endure much stiffer competition and compete against likely thirty plus other local options, all struggling to tell a great story. The small scale gin market, which is ever getting denser, more closely resembles the perfume market where there are countless perfumes. Any new option has to articulately carve out its niche in a very dense and saturated market. If you are going to throw money behind a product, especially when you barely have money, you can’t be shooting from the hip.

What I hoped was noticed was how my explanation contained useful considerations not found in the existing literature. The texts on the subject do not give explanations any more specific than because I said so. They do not help the new industry with the extremely varied conditions and the varied equipment it works with.

As I mentioned at the very beginning, gin is not seen as an agricultural product, so it has not had the benefit of great thinkers making their ideas public in the hopes to see a more distributed gin production of very high quality. At the same time, gin production has never been more important because it helps startup producers who are often definitely in agriculture, build a brand, generate much needed cash flow (as they diversity into other spirit categories), and drive rural tourism in areas that certainly need it. Hopefully I wrote something that will drive more constructive discussion and inspire others to share their knowledge.

Eventually I’m going to assemble a better annotated bibliography of gin production instead of having people rely on what is sporadically hosted all over this blog.

Metaphors From the Ground Up

In my last post, Synaesthesia, Non-linguistic Thought, and Minerality?, I spoke often of metaphors without explaining as much as I probably should have (I’m supposed to keep these posts brief because they are my least popular). I talked of grounded cross modal metaphors (think warm & cool colors) and then of once removed metaphors (minerality) and I hope to elaborate on those concepts. Just like Marshall McLuhan, I don’t explain—I explore.

I learned of grounded metaphors from George Lakoff’s Metaphors We Live By, which I kept encountering in bibliographies. Lakoff launched a thousand ships and argues very successfully that all language is metaphorical and proceeds to give a pretty spectacular tour. We often get constrained by our metaphors and I’ve since tried to champion that idea in culinary that we need to drop good and bad for the more useful ordinary and extraordinary.

Leon Adams, the director of the Wine Institute, was particularly into semantics after realizing how constrained we were by metaphors and names with congealed symbolism. A lot of the legal work Adams did was to change subtle terms within the law like the promotion of the term table wine and the removal of the term fortified wine. Adams vision was paramount to changing the image of wine from a salvage product and skid row beverage of ill repute to something positive associated with culture, wholesomeness and food. Adams oral history, Revitalizing the California Wine Industry, is full of amazing semantic anecdotes.

Grounded metaphors are grounded in bodily experience and Lakoff shows how happiness is up. I often refer to grounded cross modal metaphors and this is where one sense is described in terms of another like warm & cool colors or having sweet aromas or bass notes in perfume. Cross modal metaphor constructs get mistaken for synaesthesia, but I argue in the last post that they are merely a case of well elaborated non-linguistic thought.

Happy is up: Sad is down
I’m feeling up. That boosted my spirits. My spirits rose. You’re in high spirits. Thinking about her always gives me a lift. I’m feeling down. I’m depressed. He’s really low these days. I feell into a depression. My spirits sank.
Physical basis: Drooping posture typically goes along with sadness and depression, erect posture with a positive emotional sate.
-George Lakoff & Mark Johnson, 1980, Conceptual Metaphor in Everyday Language

I’m suspecting that the scaler adjective problem is what forces grounded metaphors to get once removed like minerality. If a shape is more complex than round or angular, it is too hard to describe so we gravitate towards something less grounded like an object comparison hence the move towards cobble stones, crushed stones, and the like.

George Lakoff also wrote a wild book called Women, Fire, and Dangerous Things which I read a lot of before it got mind meltingly technical, though I was able to take a lot of useful ideas away from it. Flavor descriptors can get strange and we don’t always know what category someone is intending to put them in. Many people refer to acidic wines, beyond their acquired tastes, as bitter, not because the wine is bitter because they don’t enjoy the dryness and they also don’t enjoy bitter things. Bitterness is a sensation, true, but in this context bitterness just symbolizes negativity. When you do not know category options well enough, these scenarios come up. We may at times see a similar scenario with “lemony”. Lemony is an object comparison, and plenty of things can resemble the aroma of lemons and share chemical compounds, but they can also simply be refreshing which is from the category of affect and not the category of sensation.

I’ve often looked at the smallest increments of things I could dream up. Something discussed on this blog a lot is the idea that art is a form of problem solving and the smallest problems a work of art can solve is anxiety, complacency, cementing memories, and retrieving memories (If Chuck Close or John Baldessari said that they’d get a standing ovation while in culinary I just generate confused looks). This framework has been invaluable to understanding the decorative in art and understanding culinary’s place in the art world.

Something else small I’ve been pondering is what the smallest increment of symbolism is (and thus the first increment in a life form?). Symbolism is the counterpart to sensation, just like semiology is the counterpart to aesthetics (and phenomenology is the unification of the two). I suspect that the first increment of symbolism is attaching nutritional value to a sensation so simple, possibly single celled organisms may have symbolism. This grew into larger chunks and billions of years later we have Roland Barthes Mythologies (which I did not enjoy because he could not explain acquired tastes).

A memory may be when symbolism binds to sensation, be it as simple as nutritional value or danger. The presence of nutritional value may be why flavor perception is so synaesthetic seeming and the co-experiences are so memorably bound. In my theories on wine pairing (contrast enhancement in space and time for food and wine interaction), I also looked at nutritional preference comparisons where contrast can be enhanced by your mind to reveal preference for a sensation. As elemental and insignificant and these tiny symbols seem, they weigh and exert pressure on metaphors we think only refer to sensations.

The mind’s complexity has definitely grown to the point where we have trouble separating symbol from sensation, and the ability of the two to manipulate us created rhetoric. We just don’t have the objective anymore because we have memory. Aromas specifically are so completely entwined with symbols (recollections) that they absolutely do not stand alone, but that is probably also the largest contributor to the pleasure of drinking wine so no complaints from me.

As metaphors for aromas get more removed from the round and the angular, like the hotly debated minerality, higher degrees of symbolism creep in. You cannot really describe an olfactory sensation or maybe you can if you state pyrazine, for example, as the chemical compound that provoked it, but that is probably overly simplified. Instead, you can only describe sensations that occurred along side it. Hence somehow you intuitively arrive at roundness. There is a movement by some sommeliers to champion the use of chemical descriptors, but I feel like they are over confident in its usefulness and not fully aware of its limitations. I should probably read more of their writing and think about it more.

Object comparisons are more symbolic than we think and they can become primed vividly in many cases while holding curiously few chemical compounds in common with what is compared. I’ve been drilling red plastic, which has pthalates that smell eerily sweet, and I’ve vividly smelt cherry so real it was almost hyper real. The experience has some mysterious characteristic like enhanced attentional contrast which may some how be the mark of a hallucination. We have a sense of how attention is distributed amongst the senses and perhaps you can feel an interruption of the normal distribution. That cherry, often even in wine, stands so vividly in place of so much that just isn’t there chemically. It must be noted that it doesn’t happen for everybody because you must have the correct library of recollections to generate it, but in so many cases we do.

Acrid is a funny term and was singled out by Constance Classen’s Aroma: The Cultural History of Smell. I’ve noted before on the blog that it refers to angular aromas and has unique phonetic convergence. Acrid may be rooted in a comparison to the haptic sense. Acrid is often used to describe the sharpest most angular aromas such as acetic acid, ammonia, or bleach. The word saw more common usage in the 18th and 19th centuries and was used to describe sharp but less extreme aromas like ginger, galangal, and cumin. The sensation of the word said aloud has a striking correspondence to the shape of aromas described as acrid.

The phonetics of our word choices are not always arbitrary and even infants have been found to match nonsense sounds to shapes consistently with adults. Euphonic convergence may have been more significant to the dawn of language, but then we quickly developed irony and started naming six foot four nightclub bouncers Tiny. Acrid may be some sort of ancient original word and I wonder if the Chinese have it as well.

Co-experience gets accumulated so mysteriously that I’ve had trouble even pondering the sources. How do we get bass notes to ground olfaction in terms of sound? Maybe there is no co-experience but there is rather just the pursuit of scale. We understand auditory scale fairly easily and possibly use it as a metaphor to explain olfaction in terms of volatility. G. Septimus Piesse was first to try and elaborate olfactory scales in terms of musical notes and his results are startlingly intuitive. 

Olfaction gets dragged in multiple directions because of co-experience and recollection so the scales never become straight forward and often get represented as a constellation or a spider graph.

shackleton spider

Descriptors are now being arranged via new ideas in data science into semantic odor space and the best work is being done in perfume. I bet soon we are going to have tons of new insights in to the dimensionality of odor/flavor space and it will power long thought impossible ideas like a wine recommendation engine that can accurately catalog sensory experiences and make truly useful recommendations. Oh shit, that is my Vino Endoxa project and I’m starting to assemble a team and make significant progress.

Vino Endoxa
Vino Endoxa: The Categories of Affect versus Sensation
Vino Endoxa: Three new categories and Pamela Vandyke Price
Vino Endoxa: Freedom and Confinement
Vino Endoxa: Vino Endoxa is Delectable and then Some
Vino Endoxa: Fine Versus Commodity Distinctions

Synaesthesia, Non-linguistic Thought, and Minerality?

Two great articles just came across my desk that at first don’t seem related, but I suspect very much are. The first comes from the team of Charles Spence (whose work I deeply admire) and is titled Where are all the synaesthetic chefs? The next chronicles the work of Dr. Wendy Parr and is titled Minerality mysteries remain.

These two articles overlap because they are both in the domain of complex issues of perception, but that isn’t the end. My theory is that perceptions of minerality are also in the domain of what many thinkers like Spence are referring to as synaesthesia, but not quite. I diverge, I think that they are wrong in attributing many sensory issues like describing aromas as sweet or acidic to forms of synaesthesia. I think rather that cross modal grounded metaphors (and once removed metaphors like minerality) are pretty standard non-linguistic thought, but I’ll elaborate and tie it all in to the minerality metaphor concept.

In Where are all the synaesthetic chefs?, the authors were trying to link synaesthesia to creativity, specifically in culinary, but not exactly finding it. It didn’t make their bibliography, but I remember reading Van Campen’s The Hidden Sense: Synaesthesia in the Arts and Sciences which looked specifically at the relationship between synaesthesia and creativity. Van Campen’s conclusion was that there is no significant link between synaesthesia and heightened creativity. What I’ve noticed is that there is a significant relationship between memory and synaesthesia. Those that can remember π to thousands of digits are mostly synaesthetes which see colored numbers. Bob Milne, the rag time piano player profiled on Radio Lab, put to use multiple forms of synaesthesia and the building of a mind palace to track four symphonies played in his head at the same time. Milne’s feat is well beyond what scientists have long thought possible with the brain. Milne turns out to be no Mozart and does not even pursue modernity in music. Synaesthesia may just help memory and contrast detection, but that is definitely not all there is to creativity.

Synaesthesia becomes a seductive nth degree situation and it draws attention away from what I think is more important which is examining non-linguistic thought. Chefs, and artists of near every discipline, are not likely to have synaesthesia but highly likely to practice extensive forms of non-linguistic thought which they have slowly elaborated and built up like a muscle.

Non-linguistic thought is best explained by Howard Gardner’s Frames of Mind: The Theory of Multiple Intelligences. Elevated levels of non-linguistic thought are characterized by heightened contrast detection in sensory modalities and increased abilities to wield one’s attentional spotlight. Enhanced abilities typically develop through practice and immersion. When these abilities go beyond what is common to a culture, we often find an artist or artisan.

Co-experience is at the center of non-linguistic thought. First, it might be helpful to hold in mind the warm and cool color metaphors (color in terms of thermoception). We typically only learn this at an intuitive level, but never dive into its theoretical underpinnings of categories, modalities, and co-experience. The binding of sensory modalities is what makes non-linguistic thought resemble synaesthesia. Where they differ is that senses bound by synaesthesia are often arbitrary though the groupings are fully elaborated. Non-linguistic thought on the other hand is bound through co-experience and therefore less likely to be fully elaborated without intense pursuit of it.

In regards to culinary and non-linguistic thought, aromas are likely to be sweet, acidic, and bitter but less likely to be fully elaborated so that they also could be salty or umami (thought some people have definitely gone there!). Synaesthesia on the other hand would be fully elaborated, and other aromas that under non-linguistic thought would have never been experienced alongside gustation would also be arbitrarily assigned gustatory categories.

Understanding and elaborating non-linguistic thought is at the center of my Vino Endoxa project to create a new data mineable descriptive system for wine (that can tackle the scaler adjective problem!). Some aromas can be described in terms of gustation and we can have the olfactory-sweet, olfactory bitter, olfactory-umami, etc. Great thinkers in sensory science have hypothesized that olfactory-gustatory linkage is a form of synaesthesia common to everybody, but I think it is more likely to be a form of non-linguistic thought well elaborated by everybody. So many aromas escape categorization in terms of gustation and it happens quite frequently in wine. Being outside of our typical relied upon categories makes these aromas more attentional, surprising, and an acquired taste, but typically pleasurable.

We find tar, cedar, dust, acridness, and minerality among other common metaphors attached to wine that escape simple gustatory classification. These are metaphors of all sorts of types and the original sources of the object comparisons among them are received alongside all sorts of modalities during co-experience because we are complex multi sensory beings. Covering it all systematically would comprise a large text, but an interesting facet of co-experience to explore is the tasting of shapes which I feel very strongly relates to minerality as a metaphor.

According to the ancient Greek philosopher Democritus, “Sweet” things are “round and large in their atoms,” while “the astringently sour is that which is large in its atoms but rough, angular and not spherical.” Saltiness is caused by “isosceles atoms” while bitterness is “spherical, smooth, scalene and small.” For a long time, I thought what was missing here was the umami and that it had unique irregular shapes whose best metaphors, because they are challenged by the scaler adjective problem (simply round and angular won’t do) is comparison to the complex, often eroded, wabi-sabi, surfaces of stones.

Long ago I had been exploring growing rock candy in bottles of green Chartreuse. Using Chartreuse’ own sugars was just a symbolic thing and also a failed attempt to have the candy absorb flavors from the liqueur. The rock candy, grown on sticks, was a garnish for a Chartreuse heavy cocktail and the drinker was supposed to find the texture and irregular angular surface of the rock candy an apt metaphor for the aroma of green Chartreuse. I never got to present it to a large group, but within my small group, however baited and biased, found sympathies between the comparison.

In the beginning of my theories on tasting shapes, because umami is the fatty acid taste, irregular, eroded, shapes rendered in the mind’s eye, were simply due to volatile fatty acids and their even more volatile esters. This can explain a large percentage of the workings of distillates like the heavier rums, but definitely not everything. Fatty acids and esters simply provide shapes, but so does everything. Wine is pretty much composed of everything and minerality is likely a collage that cannot be pinned down to an easy chemical pattern.

Something else composed of everything is the aromatized wine, vermouth. The best dry examples can conjur a sensation very much within the broad category of minerality which simply means they are complex and beyond language. Vermouths are composed of ingredients that should be able to be categorized within gustation and the culinary relevant chemical senses, but their collage like nature results in confusion. They best exemplify the scaler adjective problem therefore grounded metaphors (one sense in terms of another) just won’t do and we intuitively invent next layer once removed metaphors hence we start to get crushed stones, dusty earth, and wet cobble stones. A lot of people hate these metaphors, but they are completely within the mechanisms of non-linguistic thought.

We even often move to categories of affect like “refreshing” where higher levels of symbolic value are added. Affect can often be really confusing. When we see lemon as a tasting note, it is not always as the sensatio best compared to lemon but rather often the affect of lemon which is refreshing. We fling these context confused tasting notes so effortlessly, but when we receive them there is frustration.

Wine differs from vermouth because the source of its facets and complexity are more head scratching. Vermouth comes from sources that are relatively easy to relate to while wine comes from soil and countless subtle abstract oenological decisions.

In Minerality mysteries remain, Parr makes one very interesting hypothesis. “Only one of our specific hyphotheses was supported by the current data, namely a positive association between perceived minerality and lack of perceived flavour,” says Dr Parr. “In the absence of other flavours, it appears that wine is more likely to be referred to as mineral.” So the denser the wine, according to the study, the less likely to be described as mineral. Making a wine dense is often the choice of the wine maker and whatever accumulates later in the season as grapes ripen may overshadow and dominate minerality for attention.

Perhaps to narrow the search, we should not be looking at what contributes to minerality chemically, but rather at what overshadows it. Randall Grahm, the very progressive wine maker (and a hero of mine), is noted for observing that wines containing minerality (figuratively) live longer and resist oxidation better and hence he strongly associates minerality with life force in wine. What constitutes minerality may not help a wine live so much as what constitutes density may be a liability and decay creating further overshadowing character of increasingly ordinary and negative symbolic value.

Among thinkers like Randall Grahm, density is ordinary and not site specific, while leanness, which reveals minerality (and is often an acquired taste), produces singular site specific expressions that are extraordinary and this is a way of restating the terroir concept. It also sounds very much like ideas I just proposed for gin production.

In a look at contrast enhancement through terpene removal, I used agar clarified limes to show how removing ordinary terpenes can enhance contrast, extract features, and promote the extraordinary. It is not well articulated in the literature, but perfumers extensively use terpene removal and doing it with extreme precision is the secret of the big gin brands. Distillers make cuts in gin to remove highly attentional ordinary terpenes, common across many botanicals, and in turn to also promote singular defining aspects of a specific botanical. The ordinary often cast sensory shadows and simple experiments like exploring lime juice shows how significant they are and how little we know about it all.

Consensus may work to validate the idea that minerality in wine is a metaphorical product of tasting shapes related to non-linguistic thought (and not synaesthesia), but it will never diminish the mystery or life force in wine. We may be able to model it crudely on a perceptual level, which will help with my Vino Endoxa project, but we will never be able to find significant patterns on a chemical level. If we ever do fully explain it, I suspect all that will happen is that we find that there are no short cuts to generating it, only hard work and that will only reinforce its value within wine culture.

Creativity in the arts is the same way. Non-linguistic thought is hard won and some can push it far enough to resemble synaesthesia, confusing some researchers. The deep processes, exercises, and hard work that generate sensory linkages through learning to wield attention and empathize with co-experience also produce “creativity”. There rarely are any short cuts like some are looking for with synaesthesia. The metaphors we generate as crude translations of non-linguistic thought are merely byproducts of pursuing creativity.

New (to me) Rum Papers

I need to take a break from all this rum business to focus on the machine shop so I figured I should upload some papers I’ve been withholding so others can take a look. I need to give a big thank you to professor Robert Lancashire at the University of the West Indies for making a few of these papers available. Corresponding with him has been really enlightening.

The Chemistry of Rum Production (1947) by J.R. McFarlane

Notes on Jamaica Rum (1951) by W.L. Barnett

Trends in Rum Production (1959) H.D. Campbell
J.A.S.T.J. (Jamaican Association of Sugar Technologists Journal)

Rum Manufacture (1971) by J.A.P. I’Anson

Caribbean Rum – Its Manufacture and Quality (1987) by D. H. West and Rhett Harris

Microbial Flora of Rum Fermentation Media (1997) by L. Fahrasmane and B. Ganou-Parfait

Feedstocks, Fermentation and Distillation for Production of Heavy and Light Rums by
J.E. Murtagh


Arthur Chapman Barnes: Comments on Rum (1964)

I’m doing preliminary research for a lengthy post that tries to sort out Jamaica rum myths such as that they had various pits of stillage and lees full of banana peels, dead bats, and occasional animal carcasses. There aren’t many concrete references to such phenomena and I think the bulk of the modern myth can be attributed to Hugh Barty-King and Anton Massal’s 1983 text, Rum: Yesterday and Today (a few really smart people dispute this assertion).

Barty-King and Massal infamously reference AC Barnes whose text I just got a hold of and I am making available below his passage on rum in its entirety. Barnes references two mid century journal articles I have never seen before and I’ll be inter library loaning them soon enough. I have one other paper by McFarlane that is probably another version of what Barnes references.

What I think so far is that to a very limited degree the myths are true, but there should be a lot of ***’s. For starters I think animal bones were initially added to ferments as a yeast nutrient and the chemistry was known quite well mid 19th century. This of course got perverted by the depressions Barnes mentions when extremely brilliant entrepreneurs fled the industry. Eventually there was likely deliberate misinformation as some could produce heavy rums and some could not. Eccentric ingredients with tonal sympathies were added because it was still not fully believed that particular strains of yeast were responsible for specific character. These one time experiments grew into legends and it should be noted no eccentric ingredients are ever mentioned in the works of Charles Allen, Percival Greg, H.H. Cousins, or S.F. Ashby. But those papers were widely circulated back to London and the other islands so any funny business would severely damage the Jamaican rum brand.

I suspect the myth was again compounded by a confusion of cisterns. I believe extra cisterns existed that were not related to rum production but rather were for distillery slops holding what would go into animal feeds. If its for the pigs why not throw in the bananas. If a bat drowns no big deal. The myth is possibly compounded mid 20th century by UWI professors being given tours of sites like Hampden, observing various cisterns and seeing strange practices, then not being able to sort out their explicit functions. This a lot of conjecture but its what I have so far.

Below I’m quoting the entirety of Barnes passage on rums. The text is just too rare to not make available.

Barnes starts by dedicating his text:

The Author has 25 years of agricultural experience in the Colonial Services and in 1938 was appointed General Manager of the West Indies Sugar Co. Ltd. He was later seconded as Director of Research to the Sugar Manufacturers’ Association (of Jamaica) Ltd. He has now retired, but still acts in a consultative capacity to many large firms and organizations. His previous book on sugar, ‘The Agriculture of the Sugar Cane’ was published by Leonard Hill in 1953. The present work, an entirely new publication, will certainly maintain the Author’s already high reputation.

Fermentation Products (p.375)


The potable alcoholic product obtained by distilling fermented sugar-cane juice or sugar-cane molasses is known as rum. The name is confined to the distinctly flavoured alcoholic distillate prepared from these materials in the country in which they are produced. Under the law of the United Kingdom a potable spirit distilled from sugar-cane molasses may only be designated as rum when made in a sugar-cane producing country. The fact that sugar-cane juice could develop intoxicating qualities was known in ancient times, but the preparation of rum began much later, as being associated with the development of the sugar industry in island of the Caribbean when they were colonized in the early seventeenth century. Rum production has been a basic feature of the sugar industry in that region even since, and continues to provide a profitable method of utilizing a high proportion of cane molasses there, as well as in some other countries. During periods of grave depression of the sugar industry in the British territories of the West Indies rum was of major importance, and at times surpassed that of sugar, which might not have survived with the support of commerce in the secondary product. Until recent times the distilleries, which usually form an integral part of the establishments for processing cane, with fermentation vats, stills, and rum store near to the sugar factory, were operated by traditional rule-of-thumb methods, as some still are today.

The whole process was in the charge of a distiller upon whose experience and skill, entirely unaided by any scientific knowledge or chemical control, the success of the distillery depended. He tolerated no interference, was highly suspicious of any attempted innovation, and jealously guarded the secrets of his mysterious procedures, only imparting any of his knowledge to an apprentice selected by him who paid a substantial fee to be allowed to learn something of the intricacies of distillery operation. When fermentation was sluggish, a dead animal, a large piece of meat, or some other fancied corrective would be pitched into the offending vat. Each distillery had its special brand of rum, often more than one, the process of manufacture being related to the type of rum which the brand purported to represent. It was firmly believed that each brand of rum was typical of the sugar estate and distillery from which it originated, and that the rum sold under a particular brand could not be imitated by another distillery. It was claimed, among other things, that the soil in which the cane was grown determined the basic quality, which might be modified by changes in fermentation procedure to produce variants of the type.

Rum merchants then, as today, took objection to changes in the character of a brand, though these were often more imagined than real, and the opinion of experts in regard to taste and dour was a majour factor in marketing. It is strange that these mysteries of rum were no elucidated and exposed earlier Amalgamations of small estates with their small sugar and rum establishments, which were replaced by the early ‘central’ factory with its distillery, were one of the features of the nineteenth century. They were among the causes of more than one brand of rum being made a single distillery, but no difficulty on that account appears to have occurred either in manufacture or marketing. In the early years of this century some of these ‘centrals’ became units of much larger undertakings, losing their individuality in the new enterprises which grew the cane under unified management and processed it into sugar and alcohol in new high-capacity plants. Chemical control of factory and distillery accompanied these changes, and research exposed the closely guarded secrets of the distiller and the fallibility of the experts.

An interesting example may be described. An influential sugar company acquired a number of estates with their factories and distilleries and the brands of rum associated with them. As well as centralizing sugar production, it was decided to conduct the manufacture of rum in one distillery ancillary to the new modern factory, advice having been obtained to the effect that no difficulty wold be experienced in producing various types of rum at a central distillery. This was opinion was checked by submitting eight samples of different brands of rum from the old distilleries under secret marks to a leading expert in London, duplicates being retained for further use if necessary. Not one of the brands was correctly identified. The manufacture and successful marketing of the old brands, with some new ones, is still centrally conducted more than thirty years after this episode. In that period great changes have occurred in cane varieties and sugar-factory operation. New land has been brought into production. No segregation of molasses occurs, and different types of rum are made at convenience from the materials drawn from the storage installation. As in sugar manufacture, the ‘secrets’ of rum quality lie in chemical and technical knowledge and control.

West Indian rums are characterized by their aroma and flavour, which are generally more pronounced in rums distilled in the pot stills usually employed than in those from continuous stills. The setting of the mash, the mode of generating the yeast, and the procedure of fermentation affect the nature and extent of the secondary products responsible for those characters. These are principally esters, mainly ethyl and butyl acetates, known in the trade as ‘ethers’, so-called heavy rums containing a high proportion and light rums only comparatively small amounts. Organic acids, aldehydes (especially acetaldehyde), fusel oil, and furfural are also present. The flavour of certain Jamaica rums is due to secondary fermentations brought about by acetic, lactic, and butyric bacteria. In earlier times the heavier types were much more popular than now, but their redolent odour, which persisted for some time after consumption, has led to change in public taste to lighter types, which are distilled in column stills, and are more similar to whiskies and gins, though still possessing a distinctive character. Continuous stills enable the compounds responsible for the heavy aroma to be separated, resulting in a purer form of potable spirit more acceptable to the discriminating drinker and less objectionable to his associates.

When freshly distilled, the alcoholic strength of rum is from 40 to 60 degrees overproof. The liquid is colorless, and though of characteristic odour, bears little resemblance in flavour or aroma to bottled rums. When a coloured rum is ordered, caramel is added to produce the tint required. Rums are matured for varying periods, and are often blended to produce particular flavours in the diluted liquor sold for consumption.

The process of fermentation and distillation are closely similar to those for industrial alcohol, except that the molasses is rarely clarified, and pure cultures of yeast are not always used as in the latter. The yeast used is Saccharomyces cerevisiae, of which are are several strains. It occurs naturally on sugar cane, and no special preparation of a culture was practised for the more highly flavoured rums distilled in pot stills from mashes fermented in wood vats. From 2 to 3 gal. of molasses produce 1 gal. of proof rum. The fermentation conversion of sugar is usually more than 90 per cent, and alcohol recovery ranges between some 40 and 60 per cent of the theoretical yield.

Until about 1950 there had been little progress in production methods in the countries making pot-still flavoured rums, apart from the introduction of chemical control. For these reasons efficiencies were low, though with ample molasses available and no alternative and remunerative method of disposal readily available, poor recovery was not a  matter for serious consideration. Shortly before this the market for these types declined, a factor which directed attention to practice in countries manufacturing lighter types, with close attention to the pre-treatment of molasses, the preparation of seed yeast in pure culture, incremental fermentation, and the use of high density mashes. Arroyo conducted extensive investigations over a period of some years, and other workers also made notable contributions to improvements in distillery practice both for rum and alcohol production. The principle features of these have been reviewed by McFarlane (1949), who describes their applications to commercial practice and quotes numerous references to the original publications.

McFarlane’s views regarding the need for rum-distillery practices to be modernized in Jamaica in the light of results of research and their application elsewhere were supported in an independent discussion by Campbell (1959), who advocated changes in practice in that well-known rum producing island. His object was ‘to have Jamaica rum recognized specifically, rather than a general association of rum with Jamaica.’ This stemmed from a market survey conducted in 1957, which disclosed that while consumers associated rum with Jamaica, the actual origin of the rum they drank was not a matter of concern to them.

Bostonapothecary Machine Shop

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mill photo

I just got a metal lathe and mill as well as a new workshop to house it all so I’ll be upgrading all the champagne bottle manifolds and other carbonation tools as well as starting a culinary focused machine shop services program. I should note right off that one of my big inspirations for learning all these new skill sets was visiting the boundary pushing Industry City Distillery in Brooklyn. They set up the distillery to subsidize their machine shop and they built pretty much all their own equipment. They are very accomplished fabricators and I can’t wait to see what they do next.

To start, I’m making new manifold prototypes that have a much higher degree of precision. This is purely cosmetic, but it is still very important. Once the manifolds are cast, I can erase mold lines on the lathe or mill’s rotary table and make everything look spectacular.

A small problem I’ve been having is that the Italian company that makes the stainless 19/32 fittings changed their specs. At the moment you cannot bore them to 21/64 for a down tube then have the option of using the down tube or not. In their new spec there aren’t enough threads to catch at the top. But I can easily fix this on the metal lathe.

I’m also trying to roll the 90° flange that is on a 5/16 stainless keg down tube. These are probably done on a very specialized pneumatic press and it is very different than a stainless brake line flange. On the small scale, no one seems to be doing anything similar in stainless steel, but I have some leads on a technique which involves pulling the flange with a live center mounted on a tool post while spinning the tubing.

I’m also going to mill new molds for the food safe silicon seals. The seals have to be centrifugally de-aerated in a Jouan C412 centrifuge because pressure and vacuum are not enough for the extra high durometer material. I plan to make them so they can nest and I can stack them five high in all four centrifuge cups.

I developed a new technique where I can precisely mold reliefs of engraved objects then use a rotary table to mill out recesses on the prototype to hold the precise castings. The flat cast reliefs can then be curved around the round prototype (eventually I’ll have pictures). Basically, I can start to brand the manifolds either with engravings I’ve collected or specially designed for brands that want to sponsor them like Campari®. With a good setup I anticipate I can do these in both very short or very large runs.

As far as my culinary focused machine shop service goes, I will be volunteering shop time to help very high end culinary programs, particularly kitchens, bring ideas to life that otherwise might not be economically viable. If I agree to a project they will only have to cover the material which is often quite low. Ideas are piling up and hopefully I can inspire other hobbyist machinists to also collaborate in the name of profitless art. Restaurants move money, but they don’t exactly make money so many ideas just can’t come to life. At the same time, there are countless garagiste machinists that make steam engines and model rail road gear just to have something to make. If we can bring these two groups together, culinary greatness might happen.

What I envision are very simple things like a gear for a broken machine, a precise food safe seal. A small food safe mold. Small milled parts to bring antique equipment back to life. For slightly larger projects, I want to make food safe inserts for centrifuge cups and then other larger objects. To do bigger jobs I have the use of the Bridgeport mills and larger lathes at the Artisan’s Asylum.

For very complex objects, I want to make a rotor stator blender bowl for a Vitamix to push the boundaries of homogenizing liquids. This will be similar to my colloid mill but using a blender motor and designed only for liquids (I also have to make some new food safe parts for my colloid mill). I’m also conjuring a peristaltic pump type beer engine that might even have an archaic steam punk style to it.

More to come. Feel free to hit me up with ideas.

The aesthetics of lime: contrast enhancement through terpene removal

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If you are a commercial distiller, flavor chemist, or over achieving bartender, you may want to read the prequel to this article, High Fidelity Gin Distilling / Perceptual puzzles / Musings.

Long ago, from Gordon Shepherd, I learned about contrast enhancement in the olfactory sense. In his text, Neurogastronomy, he likened many of the phenomena within olfaction to other senses like vision where contrast enhancement and its mechanisms are better understood. This led to my still leading theory of wine & food interaction: Contrast Enhancement in (Space & Time) for Wine and Food Interaction.

Contrast detection and contrast enhancement are still both poorly understood and little explored in the culinary arts. Neurogastronomy opened my eyes, but it has been slow to launch other ships. Since then I’ve learned more chemistry and even more about aesthetics and have slowly begun to apply some of Shepherd’s ideas to cocktail and distilling problems.

A big problem I came across was how the hell do terpenes work? Do they have any parallels with the esters, which in regards to still operation, are better understood? We can talk about this abstract stuff on paper, but can we ground it easily in an accessible sensory experience that provides an nth degree lesson? Enter clarified lime juice.

I remember the first time I made the FCI’s clarified lime juice. The recipe is brilliant, though I didn’t exactly enjoy the product and I don’t think its creators realized what exactly they clarified from the lime or its implications to understanding other processes, but I did quickly come up with a beautiful cocktail:

.75 oz. mezcal
.75 oz. milagro mandarin (not sure how this made it into the house)
.75 oz. der lachs danzig goldwasser
.75 oz. FCI clarified lime juice

I may have made the comparison of clarified lime juice to “Rose’s lime acid” which sort of compares an idea that is thought to be cutting edge with something plebian and ordinary. It definitely aroused the wino in me and I denounced it as against terroir. It is everything many of us complain about in overly manipulated wines, though few others seem to share that opinion.

Back then, I didn’t know that the big difference, before and after clarification, was with the terpenes, they’re pretty much all gone. Weakly soluble terpenes get bound in the agar which is separated by centrifugation. If you haven’t experienced any clarified lime, in the mind’s eye, it sort of glows neon like Rose’s and though its wholly natural, it seems so artificial. Terpenes are the class of compounds that gives lime (and so many other things) its piny character. They contribute an extraordinary timbre when fairly fresh, but then degrade into something very ordinary and pine-sol like as they oxidize.


Patterns were beginning to emerge between these sensory experiences and all the things I’ve read. Joseph Merory’s very elaborate recipe for orange liqueur is all about terpene removal. The primary explanation (because I said so!) of why its done is pretty much left as to improve stability and reduce cloudiness as terpenes come out of solution because they are so weakly soluble in water (think louching absinthe), It is not widely acknowledged that there are big aesthetic consequences.

Infused orange has all its terpenes intact and that gives it a more irregular shape rendered in the mind’s eye where its roundness is juxtaposed with the abundant angular terpenes. This is especially true as you get away from sweet oranges into the Sevilles and sours. Cointreau, which is distilled, glows like Rose’s and clarified lime juice. It’s aroma has perfect roundness and near no slight angular facets, because when its distilled, the terpenes are carefully cut away. Actually, they might be retained to very selective degrees and that might provide nuance and identity to the different brands (besides the other aromatic adjuncts like coriander and the mints, etc).

So far I’ve just used the term terpene as a catch all, but there are so many types just like the esters. You can get PhD’s in terpene science that will take you far away from here. Some aromatic terpenes are noble and some are less so just like the esters. Some are particularly volatile and some less so. Some are significantly effected by heat and some less so which is why vacuum distilling is popular in terpene territory.

Making, blending, and drinking clarified lime juice might just be that accessible nth degree exercise I was looking for, but how can we wrap more language around contrast enhancement? What we are doing when we clarify lime and blend it back in with plain lime is extracting and blowing out features. Sharper divides are created between the various spatially perceived facets of the experience. What we are creating is a sort of noirish effect. We are going down David Lynch’s Lost Highway. We are also creating a super normal stimuli (remember that forgotten nobel prize idea I’m always talking about?).

All creative linkage in the culinary arts is governed by the principles of the super normal stimuli and so is the joining of terpene free lime juice and normal lime juice. Features lurk under the olfactory shadows cast by those terpenes. To use another metaphor, when the ratios get changed, the ass on that lime, that part that resembles Rose’s, blows up. Where there was a response tendency, there is now an exaggerated response tendency and you’re going to chase it down the street. This is subtle and is governed by our ability to even detect contrast in the first place which is not always the most refined. If we can harness and wield these concepts just articulated, we can create more seductive gins and that is the real prize I’m after.

In truth, these gins have already been created. Terpene management for the sake of contrast enhancement is at the heart of the leading gins on the market, but its never articulated that way. Saying why we enjoy this thing we take for granted becomes a thing in itself. It also opens doors for small producers instead of only the chromatography wielding genius architects of the big gins.

There are simple ignoble terpenes that are the equivalent of ethyl acetate or acetaldehyde which are congeners that distillers are typically more familiar with. When concentrations are too high they can come out of solution and that is a big negative because most styles of gin should be brilliantly clear. They also bridge aromas like simple esters often can. The perceptual bridges reduce those defined lines where things really pop which is our contrast enhancement phenomenon.

Aromatic bridges are features or flaws depending on the context. Concentrations of compounds also change when above the various thresholds I’ve discussed before. There are absolute thresholds and recognition thresholds and the rules of thumb governing esters likely also apply to the noble and ignoble aromatic terpenes.

Gin producers tune their stills to get the results they want. Most of the time they don’t actually know how to rap language around what they are getting or where they want to go. They just tuck in a cut, reduce the heat with partial vacuum, vary reflux, modify time under heat by applying more or less energy to the boil, use a gin basket, and pretty much systematically try everything. Basically its all more cow bell and then gets sent to a tasting panel for consensus.

The parameters get varied and the product is examined to be relatively more extraordinary. Chemical compounds are also counted up and correlations are found between what is ordinary and what is extraordinary.

We find ourselves in the territory of the ordinary and the extraordinary and its all about the frequency of occurrence of the aromas sets and their relationships. This was modern for a while and most certainly was in the 1990’s when the big gins went turbo via their semi-secret in house research programs.

What happens when we go post modern? When everybody learns the trick and we are saturated with high contrast experiences? Did the whole world go noir? Of course not. We eventually attach symbolism to sensory experiences and that helps resist initially seductive aesthetic experiences. I pronounced the clarified lime juice as artificial right away which is purely symbolic. Humans have a more complicated relationship with supernormal stimuli than do animals (for animals, it always leads to their doom). The Australian beetle tries to mate with the bigger, more orange, more dimpled beer bottle and it dies out (or they famously change the design of the beer bottle).

For gins these days, the most extraordinary to me, have been ones that have juniper from far flung latitudes and close proximity to the coasts. This is funny because pretty much no one talks about juniper sourcing. Classically these are not desirable sources, but they are so uncommon, and you just know they are from the nether regions, so the symbolism of terroir creeps in and they get prized by me, a wino.

Some new classes of gins I’m finding extraordinary are partially infused. I don’t completely understand their chemistry, but I think this gives them acidity which makes them sippable even at room temperature. It is a genre more people should explore.

So now we have grounded this terpene business in all sorts of things people can relate to and hopefully we have a useful framework for contemplating the experience. I propose every one drinks several daiquiris arranged in an epic flight just like some of the varied contrast photos above. Make sure to make full sized drinks because the lesson really needs to sink in. To vary the contrast, mix different ratios of untreated lime and clarified lime. Your drinks should look like this:

 .75 oz  lime (1:0, 2:1, 1:1, 1:2, 0:1 clarified lime juice to unclarified lime juice)
8 grams non-aromatic white sugar
1.5 oz. unaged Cape Verdean rum
stir in the sugar to dissolve then shake with four cubic inches of ice

Watch a waxing and waning moon unfold within your mind’s eye. To help create the lime juice ratios, use the kitchen scale to measure juice by weight instead of volume. Alternatively or in conjunction, a pipette is helpful.

Now that you’ve experienced it, lets back up for a minute, reference the prequel, and touch upon those olfactory shadows cast by the terpenes. The terpene literature leaves a lot to be desired and the lessons all just end in because I said so. Lets quote Gary Reineccius again:

Terpeneless and concentrated citrus oils from which only a part of the terpenes have been removed are widely used as flavoring materials as they have improved stability and a longer shelf life, a lower usage rate, and improved solubility making them of particular value in the flavoring of soft drinks and liqueurs. -Flavor Chemistry And Technology, Second Edition by Gary Reineccius.

Hopefully the curious language that is popping out is lower usage rate. That is the language Reineccius came up with to describe the contrast enhancement phenomenon. Something perceptual happens but he couldn’t encircle it with language. He was not confident enough to say something like there was a change in threshold of perception, but he recognized the usage rate in formulations went down. When there is less to overshadow the the glowing lime, it pops and you need less. Hopefully my metaphors do the topic justice, but I’d love to hear some feedback.

I’m not really sure how this will be received. There will be aha’s! and epiphonies, there will be confusion, disbelief, and denouncements. There will be those that got to the end and never figured out what I’m talking about. If you are in the direction of the later, I urge you to drink more, make a pilgrimage to view a Caravaggio, or rewatch Sin City while drinking the above daiquiris.

You can also sign up for my aesthetics workshop at the sMFA this fall.

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