Technology Transcends Heritage in Modern Distillery Practice, 1937

Follow along: IG @birectifier

VOL. 44 • CHEMICAL & METALLURGICAL ENGINEERING • No. 4 APRIL 1937

---

I saw this and thought, C.S. Boruff, that guy was known to be opinionated… and he certainly is. Here is a very unique vantage point from the restarting of the whiskey industry right after prohibition. What you read may remind you of Rafael Arroyo and they were known to correspond. Boruff, however, may have been a little too sure of himself and some ideas did not work out. The industry backed away from pressure cooking as described here because of the burnt popcorn character it gave to corn. Distillers also sought places to let distillery character creep in and even though they selected better grains and adopted sanitary handling, many kept putting their mashes in old fashioned open top wood fermenters.

This article never mentions the three−chamber still, but you can glean a little of why it was phased out. Sloppy ferments from inferior grain often needed higher ABV distillation to clean them up if you were not going to invest in corrective aging. Those lighter distillates may have needed “grading up” with heavy three−chamber distillate. If you could keep a higher average quality, you may not need that burly high quality, but certainly expensive, three−chamber distillate. Possibly the only three−chamber stills in operation after prohibition were Calvert in Baltimore and Hiram Walker in Peoria, Ill, but after their lifecycle, they may have been traded in for the idea of “predetermined whiskies” distilled exclusively on continuous stills.

Technology Transcends Heritage in Modern Distillery Practice

By C.S. Boruff and L.P. Weiner
Technical director and superintendent Hiram Walker and Sons, Inc., Peoria, ILL.

Presented under the title, “Advances in Modern Distillery Operations,” at the Baltimore meeting of the American Institute of Chemical Engineers, Nov. 11, 1936.

Before prohibition, whiskey-making was regarded more or less as some form of mysterious art. The methods of production and the yeast used were jealously guarded and handed down from father to son in the manner of a heritage. Use of poor quality grain, unsanitary handling at all stages of manufacture, and the use of crude and antiquated equipment gave the distiller a low yield of the desired higher alcohols, acids, aldehydes and furfural, and a large quantity of undesirable volatile fermentation products such as allyl alcohol, acrolein, butanol, butyric acid, and sulphur and nitrogen compounds. All of these were included in the whiskey as barreled, with the result that long periods of corrective aging were required in addition to the natural maturing.

Unfortunately for the industry and the public, repeal of the 18th Amendment saw most of the old distilleries put back into operation under the same type of management, using the same type of machinery, and employing the same methods of manufacture as had been used fifty years before. From a technical point of view, the industry was still operating as of the 19th century, and to add insult to injury, various distillers advertised that they were making the same kind of XX° whiskey as grandpappy had in 1880.

Fortunately, a few distillers built upon their previous experience in making whiskies, preserved all that was good and sound in fact, capitalized upon their years of experience, and most important of all, called upon modern methods of processing, handling, and controlling all operations. Mechanical, chemical, and biological control became a reality in these few distilleries. All variables in manufacturing were put under automatic control. Processing was conducted in a sanitary manner which produced a clean fermentation and hence a clean beer free of all undesirable constituents and containing the proper quantity of the desirable congeneric products.

The writers wish to present here some of the “old time” methods in contrast with the modern methods of production and control.

Grains

The grains most commonly used in distilling operations are corn and rye. Malted grains are used for converting the starches in the primary grains to sugars for fermentation. Because of their inherent suitable qualities, barley malts and rye malts are used in most cases. Despite minority denials, research and production data have proved that the manufacture of distilled spirits is no exception to the universal rule that “quality starts with the raw materials.” In the “good old days” there seemed to be a myth among some people in the industry that any kind of grain was good enough for the production of whiskey or spirits. Good distillery operations now demand corn at least two grades higher than that formerly known as “distillers’ grade.” Poor grain is apt to contain mold and possess a high bacterial count. Excess bacteria induce undesirable side fermentations which compete with the main yeast fermentation. As a result of these side fermentations, such undesirable volatile products as butyl alcohol, allyl alcohol, acrolein, and acetone develop in the fermenting beer, and they cannot be eliminated entirely no matter how fine the subsequent distillation and rectification. No grain should be accepted into a distillery until it has been properly sampled and passed by the control laboratory. Very rigid specifications regarding bushel weight, starch content, damage, dockage, mold content, frost-bite, moisture content, and, most important of all, bacterial count, should be adopted. Government and Board of Trade specifications alone are not rigid enough to exclude all undesirable shipments.

Grain Handling

The old-fashioned distillery unloaded grain by moving it with a hand or power shovel from the grain car into an unloading boot located on the ground or recessed in the ground below the unloading doors of the cars. From this point either screw conveyors or bucket elevators conveyed the grain, together with all its refuse such as husks, cobs, dust, soil, etc., into the grain storage bins. Sometimes grain cleaning was practiced. For the most part the storage bins were merely wooden hoppers which were totally unsuitable for the sanitary storage of any perishable material such as grain. The operators knew little of the importance of clean grain although most of it was inspected for mold. Good practice today dictates the unloading of grain directly from the freight car by means of smooth, cling-proof sanitary metal tubes coming from exhausters so that in effect the grain floats upward through the tubes into smooth glazed concrete storage bins which are totally enclosed and which have no crevices or abrupt corners for grain to cling to and rot.

In the old days, it was general practice to grind a large amount of grain at one time so that the “boys could go home.” This milling was really “pressure grinding” and was accomplished with hammer or burr mills. Such mills give grain an unusually hard treatment in that considerable heat is generated during the grinding operation. The grain is scorched and is well on its way to deterioration within a few hours after it leaves the mill. While some of the old distillers used roller mills, the highly refined roller mills in use today were not available. Today we find the modern distilleries equipped with three-high six-roll mills which are in effect three separate pairs of cutting rolls. Thus milling is accomplished in three gentle cutting stages and heating is reduced to a minimum. The corrugations on the various rolls are kept in good condition by grinding and corrugating machinery located on the premises.

Modern distillers grind but small amounts of grain at a time so that the natural bouquet of the grain is preserved and the tendency toward deterioration, which sets in as soon as the protective coating is removed from the grain, is reduced to a minimum. Here again the vacuum tube replaces the bucket elevators for conveying the meal from the mills to the meal storage hoppers. The same smooth-surface, concrete storage bins are in evidence with no openings except the few tight-fitting manhole covers for inspection and cleaning.

Those who knew the old distilleries will remember the meal scale floor as a place where a respirator was required in order to breathe properly. Meal was generally dumped out of the large hoppers into smaller wooden ones on rollers and these in turn weighed on floor scales. The portable hopper was then rolled to a hole directly over the open mash tubs and the meal dumped in.

It is a far cry to the sanitary operations of today where meal is withdrawn through closed piping systems, weighed automatically and delivered through additional sanitary closed systems to modern pressure cookers. This is accomplished without any more physical effort than pushing several buttons. The operator’s energies are left to watch and control other processes.

Mashing

Before the meal can enter the fermenters it must be “mashed” and the solubilized starches converted into sugars. Years ago, and in many of the plants today, mashing was accomplished in wooden or metal mash tubs which were open vertical tanks generally with a conical bottom and having an agitator coming down through the top or up through the bottom and bearing many wooden or metal “sweeps” or “rakes.” Inside and on the bottom of the mash tubs were bolted stationary sweeps or rakes to break up the mealy mass as it was mixed with the water that was added. One can imagine the difficulty of properly cleaning and sterilizing such a vessel and its internal contrivances. Also, as might be expected, all of the starch was not brought into solution by the cooking action of the steam coil in the bottom of the tub because of localized heat, improper agitation, and lumping of the meal and water. Later, when the mashing was completed and the malted grain meal added, the maximum amount of starch surface was not exposed to the action of the diastase of the malt, and incomplete conversion resulted. This unconverted starch led to low yields and undesirable fermentations. In any fermentation process the best quality of distillate is always accompanied by the highest yields, yet there are those today who believe there is no such relation. Some even go so far as to advertise that it takes more grain to make a gallon of their whiskey than it does other whiskies of the same type.

Today modern, completely enclosed pressure cookers are used for mashing grains. By the very nature of the principle of pressure cooking, it is easily possible to attain temperatures well above the sterilization point and to quickly gelatinize and solubilize all starches without any harmful effects on the grain. A pressure cooker can also be sterilized with live steam after the cooking has been completed. The advantages of this complete pressure sterilization over that which can be accomplished in an open tub under atmospheric pressure cannot be emphasized too greatly.

In a modern distillery the conditions for optimum cooking, mashing, and conversion are watched over by the control laboratory. Samples are collected in order to be sure that conversion is practically complete before the mash is sent to the fermenter and that the mash still possesses sustained diastatic activity.

Fermentation

Have you ever seen wooden fermenters in an old-style distillery? These fermenters were merely open top wood stave tanks bound together with trussing irons and equipped with wooden bottoms generally pitched to one side to facilitate draining. By the nature of the porosity of wood and the number of joints between the various staves, breeding and hiding places were provided for bacteria that are always ready to live and multiply where they can find food. It has been reported that it was no uncommon sight to see flies, and occasionally rats or mice, floating around on top of the beer in these open fermenters. After emptying such a fermenter, the best the distillers’ men could do was to enter it with boots, hose, and buckets of lime water to whitewash the inside and attempt to sweeten it somewhat before refilling.

Modern distillery fermentations are conducted in closed-top, alloy-steel fermenters which are shaped gracefully not only to please the eye but also to eliminate possible lodging places for any sort of dirt or bacteria. Such fermenters are equipped with automatic high-pressure, high-temperature, water-washing devices that revolve and spray the inside surfaces of the fermenter with boiling water. These fermenters are also equipped with copper tempering coils supplied with cold water and controlled with automatic controller-recorders so that any predetermined temperature of fermentation can be maintained at all times.

Samples of the “set fermenters” are always collected by the control laboratory, and acidity, pH, and balling data are recorded. If the set acidity is not correct, it is regulated. All fermenters should be mixed daily with carbon dioxide gas and samples checked by the laboratory. The rate of fermentation is regulated in order that the fermenter will be finished on scheduled time and that only the desired congeners are developed and these in the proper quantities. Through proper selection of grain, mashing procedures, yeast, sanitary operations and control of fermentation rates and temperatures, one can produce a clean beer, free of undesirable volatile fermentation products—a beer that following distillation at between 100 and 160 proof will give a stock that requires only natural maturing in a barrel, and no corrective aging, to produce a balanced, clean, and mature whiskey. By careful control, both higher yields and higher quality are realized.

Distillation

A relatively large amount of money is required to operate even the smallest distillery, because the financing of maturing whiskies entails considerable working capital. Therefore, only the large distilleries can afford to install all the necessary equipment for accurately controlling all operations. Whiskey can be distilled in a collection of old pots, pans, cans, and pipes or in a hundred thousand dollar still, but what a difference in the final product. Few distilleries can afford to install and keep in operation the several different types of stills which are necessary to better produce different whiskies. There are really only two general types for producing whiskey: one, the pot still or variations such as the simple batch still, and two, the continuous still. The pot still may be merely a kettle wherein the alcohol is boiled off and condensed but this type is not in general use in the United States. More generally the type of still used is what is known as a beer still, which operates by boiling a batch of beer placed in its kettle, condensing the alcoholic vapors and possibly redistilling the resulting distillate in order to purify and “develop it” further. In distilling from such a still either all or any part of the undesirable distillate recovered at the beginning and the end of the distillation may be taken out by more or less inaccurate methods of discarding the early and latter part of the run into separate heads and tails tanks. In operating a continuous still the fermented mash is constantly fed in at an even rate and the whiskey and grain residue drawn out at an even rate. Various reflux ratios can be set with a consequent variation in the body or type of whiskey produced. Also, a uniform amount of aldehydes or heads can be withdrawn from such a still while in continuous operation although this withdrawal is not necessary or even advisable if a clean fermented mash is used as feed. Controlling the beer input temperature, the temperature and rate of distillation, the temperature and quantity of water wash in the wine plates, the reflux ratio and the temperature of condensation of the distillate vapor, constitute the vital points of distillation control. Engineering progress has played an important role in these operations by providing suitable automatic controlling and recording instruments. Temperatures, for instance, are controlled to within one-half of one degree. This spells uniformity of product and is quite different from the old time method of operation where the distiller or “beer runner’’ operated the still to the best of his judgment and empirical training rather than according to predetermined standards based on scientific knowledge.

Suitable high wines storage space should be provided and samples of all distillates examined by the laboratory and “quality committee” prior to pumping to the cistern building where the whiskey is drawn off into charred barrels. Distillates that do not match standards in analysis, body, bouquet, etc., should be returned from the high wines department to the stills for redistillation or conversion to spirits. Such a procedure will insure uniformity of product.

Predetermined Whiskies

Through research studies we have been able to determine why different whiskies require different maturing times. Likewise, these studies have indicated the desirables and undesirables in a distillate and the source of each. On the basis of this knowledge, we are now able to design and manufacture whiskies of various bodies that will mature at any desired age, the program or method of manufacture differing in accordance with the desired maturing age. The old-fashioned and common production method today is for each distillery to make one or two distillates which it uses for all ages of whiskies. When sufficient stocks are available the distiller increases the age, the product eventually becoming a “Bonded Whiskey.” If a particular whiskey is best when it is four years old, how can this same whiskey be considered a quality whiskey at one year or two years of age?

Designing and producing predetermined whiskies that are clean, mellow, balanced, and mature at ages ranging from three months to six years, is a reality at the Hiram Walker plant. All this has been accomplished through exhaustive studies of all variables and by putting all processes under strict control. No artificial aging methods have been found that even approximate the accomplishments that can be obtained by merely controlling the “natural processes.”