Knowing Botanicals

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After launching my own birectifier production, I am about to launch my own production of the best Clevenger apparatus design for gin distillers. It will be affordable and well tested and it is proving to be so easy to use, it should be standard equipment for any gin distillery. This has coincided with revisiting some old documents I’ve collected over the years on gin production that I have not shared. Somewhere, I even have Seagram original botanical formula from the late 1930’s.

Currently there are few tools & strategies to maintain gin quality other than setting up soleras of both botanicals & distillates. The next wave of advancement is very likely the analog analysis tools of the 1940’s. Something unique about this situation is that many of these tools are cheaper than they have ever been. The Clevenger apparatus I’m producing is probably cheaper than Seagram paid for theirs. ABBE refractometers, in the olden days, could only be purchased new for thousands and now eBay is littered with a near infinite supply from the best manufacturers. The educational hurdles of learning these tools are also the cheapest they’ve ever been because of Youtube videos that directly cover procedure and our ability to rapidly converse with educators, eager to share knowledge, that have direct experience with these tools.

The internet also opens up a foundation of basic science to understand what we are trying to look at. Previously this basic science foundation would have to be privately built by a firm. Now a data sheet on coriander is just a google away. What refractive index should we expect from coriander oil (1.4569 to 1.4700)? That information was expensive to built, but is now just our public domain inheritance.

	% Oil	% span	Specific Gravity 15C	SG Maximum	Optical Rotation 20C	Refractive Index 20C	Seeds per gram
Coriander	0.5 to 1.0	100%	0.870	0.8850	+8 to 15	1.4569 to 1.4700
Caraway	3.0 to 5.0	60%	0.907	0.9200	+70 to 82	1.4885 to 1.4890
Aniseed	2.5 to 3.0	20%	0.975	0.9900	0 to -2	1.5530 to 1.5600
Fennel	4 to 5	25%	0.860	0.9550	+6 to +24	1.5250 to 1.5500
Angelica root	0.75 to 1.0	33%	0.857	0.9180	+16 to +32	1.4770 to 1.4880
Angelica seed	0.3 to 0.5	60%	0.851	0.8900	+11 to +13	1.484 to 1.491
Licorice	****		–	–	–	–

Above is some preliminary data we can start with and expand upon. One of the first things to note is the spread of essential oils. Coriander, the number two ingredient in a gin, exhibits the most variability. It’s essential oil yield can vary by 100% and no doubt sees qualitative variation. Measuring that essential oil yield so the botanical charge can be scaled may only take 20 minutes of active time and a $300 piece of laboratory glass with a few accessories like a heating mantle. Qualitative fluctuations can be understood with tools like an ABBE refractometer that may also require less than 5 minutes of measuring time. These processes are far more sure footed than relying on a solera. In gin production, a lot of open ended judgement gets delegated to inexperienced labor when, often and for the same amount of time, concrete analysis tasks could get delegated that are framed by the data & judgement of experts (and founders).

A concept that was new to me is that coriander oil varies in yield with ripeness but also significantly qualitatively. Eastern and Western cultures also have polar preferences. Western preference is for over ripe coriander where the essential oil yield may average 0.60% whereas Eastern preference is for greener under ripe coriander which may be more penetrating in character. The London dry gin tradition is probably all with ripe coriander. However, green coriander may open the doors to new gin categories. The space in between may be full of qualitative change that must be navigated. Counting seeds per gram may also be a strong qualitative predictor as well as correlated to oil yield.

[One thing to note here is how close the “% oil by Clevenger (dry basis) is to “% essential oil (dry basis)”. The latter measurement is from the more expensive soxhlet extraction method.]

Caraway is different than coriander and the essential oil yield increases with ripening. My understanding is that caraway is more prone to essential oil loss during storage than other botanicals. Some sources report more yield variability than the data in the table. Wild caraway may have as much as 9% essential oil. How do you build a product that relies on traditional co-distillation of botanicals that sees such variability without analysis? You basically could not touch wild caraway without a Clevenger (which is a beautiful marketing concept). There is also qualitative variation. According to the Seagram team: “In the unripe fruit, the quantity of limonene is predominant; as the fruit ripens, limonene oxidizes into carvone.” Carvone is minty, but changes in its stereo chemistry make is more of the prototypical caraway scent.

What happens if you are shopping the world supply of botanicals and trying to achieve an effect? Many farmers who deal with buyers more savvy than gin distillers often use these tools. Before purchasing, could you ask the caraway’s oil yield and refractive index (which is a proxy for its ripeness)? What will our opinions look like when more of us truly know botanicals and how will a specialized market communicate? Botanicals are the stock & trade of the gin distillery producing a high margin luxury product so distillers should be as savvy as they come, but what we see is that low margin farmers in poor countries are more savvy and make larger investments in understanding their own product. The farmer likely even has data that could inform the gin distiller, but the distiller does not know how to take advantage of it.

There is a lot to build upon here and this document may grow. How do we develop preferences on selecting angelica root over angelica seed? Both roots are “peppery”, but the root can contribute muskiness and is thought to be a minor radiant. How do licorice hydrosol’s work from an analysis perspective? Licorice does not have an essential oil that can be isolated by a Clevenger. What does licorice contribute? It’s character is often described as “irritating” and may stimulate the trigeminal nerve. That sort of stimulation is known to enhance olfaction and reduce the threshold of perception of odorants.

When do we choose anise seed over fennel seed? or how to we elaborate on one of them to instead use both? Anise seed may have 1.4% essential oil while fennel seed can be as high as 4.0%. Trading one for the other would require a wildly different weight to achieve an equivalent quantity of essential oil! (assuming a similar threshold of perception). Seagram notes that “Commercially, two kind of fennel oil are distinguished: i.e., “Sweet” and “Bitter” fennel oils. The former has a flavor which closely resembles that of anise oil. The bitter oil resembles turpentine. The chief constituent of the sweet oil is anethole (60%) and fenchone (10-15%). Bitter oil has less anethole and more fenchone. Both kind contain the terpenes alpha and delta pinene, camphene, dipentene, etc.” So how do we even know what we are buying is sweet or bitter fennel seed? Would a refractive index be our fastest proxy for fennel’s that are in the ball park for a house style? Anise seed is more simplistic and may contain as much as 80-90% anethole and only 1% fenchone.

[One thing to note here is how close the “% oil by Clevenger (dry basis) is to “% essential oil (dry basis)”. The latter measurement is from the more expensive soxhlet extraction method. Notice, they are rejecting the above Russian anise seed.]

Countless options for gin botanicals are not even part of this discussion yet. No citrus peel data? Who could help us there? All I can tell you right away is to take the Clevenger apparatus seriously.

[Recently I made a triple-sec from one type of peel, Seville orange, and I nailed an ABV, sugar content, and aroma extract level that matched Cointreau, yet it was not as glowingly good as the industry leader. However, it was quite good in a cocktail. What I want to learn more about is the difference between sweet orange peels and those considered bitter or sour. My bet is that they may differ in acid number. To find that you would use Seagram protocol of creating a standard slurry of the peels and titrating it. This is important to me because I may move to a citrus region. I may encounter peels galore and need to know how to classify them and then harness their aroma. I will probably make more triple sec. Joseph Merory used had a triple-sec recipe that was 17.5% sweet orange oil relative to bitter orange. It even had lemon on top of that and then adjunct botanicals like nutmeg & coriander.

Another formulation from Merory is roughly 2/3 bitter orange peels to sweet. It also sees orange blossom. Merory has yet more formulations for Curacao oranges, but I’m not sure if they are classified sweet or bitter. Some oranges, due possibly to how they are peeled & dried, require more terpene separation than others. What I don’t quite understand is the difference after separation. Terpene separation is the main driver of the glow of modern triple-sec. Generic terpenes cast shadows and removing them makes the essential oil underneath brighter. Much generic terpene is in the pith and more careful peeling may reduce it, but I can’t say if anything else is compromised.

Peels are extraordinary raw materials that are hard to get good first hand knowledge with. You are stuck paying significantly to play and that is often beyond my resources.