Distiller’s Workbook exercise 1 of 15

This is the umpteenth draft of the first lesson in my Distiller’s Workbook. I started it as a book project with the idea of generating interest in distillation by showing a simplified form of it based on the re-distillation of tax paid commercial products.

Over time, the recipes have been elevated from merely low involvement cocktail-centric creations into being a workbook of exercises for new distillers to learn big concepts in distillation on small scale equipment with affordable batch sizes. Hopefully new distillers will be able to learn most all the what if? scenarios of operating a still so they can instead deepen their involvement with the sourcing & processing of raw materials, fermentation, and then the maturing of spirit.

A big focus of the workbook is to expose new distillers to the giant body of research concerning the subject via referencing it. I started by collecting every book on the distillation I could find and that still left a lot of questions. I eventually started collecting forgotten and seldom seen journal articles. These were newly digitized or trapped behind pay walls and I have read hundreds in the last few years. Most professional distillers do not even know this massive body of work exists so I hope to weave it into the content and introduce it to people.

Tabasco Aromatized Gin

The aroma of chilies can be a thrill in gin and it is surprising their usage is not more common. A favorite source of chili aroma is from the iconic condiment, Tabasco, and using it to aromatize a gin will teach a lesson about the volatility of fatty acids and how they can be manipulated.

In front of all that great chili aroma in Tabasco is undesirable volatile acetic acid which is used as a preservative. Acetic acid is a short chain fatty acid and is volatile at the temperatures we are concerned with. The boiling point of acetic is actually higher than that of water at 118°C, but its relative miscibility in water and ethanol allows it be volatile at lower temperatures and therefore enters beverage distillates.

S. H. Hastie, the early Scotch scientist, used a trick in one of his experiments when he was trying to isolate and unravel the role of fatty acids in forming esters in the still via the esterification reaction. The trick was to essentially lock up the acids by forming a non-volatile salt with an alkaline additive. Hastie used lye but we can use something gentler like baking soda.

Every now and then the same idea is used to salvage pricked or vinegar tainted wines. The unsellable spoiled wines are taken to a distiller with the intent of making a neutral spirit. To help render the spirits neutral, the wine is treated with an alkaline additive to lock up the volatile fatty acids as salts. Once the salts are formed, when the wine is distilled there will be less volatile congeners to separate by fractionation or making cuts.

We can use Tabasco to aromatize a gin, but not other spirits like brandy or whiskey which have aromas defined by fatty acids and esters that would be damaged or detrimentally augmented by encountering the alkaline additive. Gin, which starts with a neutral spirit and derives it’s aroma from botanicals, is virtually free of fatty acids so there is nothing that will be lost to the baking soda. A whiskey on the other hand, has no appreciable acetic acid of its own, but it does have other longer chain fatty acids that could be trapped as salts and therefore stripped away.

Keep in mind that the pricked wine can only become neutral spirits. In the wine, the acetic acid alone cannot be targeted because the alkaline additive will form salts with all the fatty acids present (as well as the other non-volatile acids). Aromatizing a gin with Tabasco is a unique scenario where only one fatty acid is present which gives us the opportunity to illustrate the concept in a beautiful context.

Some people maybe be thinking of trying this with other vinegars like apple cider or balsamic, but keep in mind, their aroma which we love is the product of other fatty acids besides acetic. When the acetic acid is neutralized, other fatty acids will be lost to non-volatile salts as well.

A still can be run fast or slow by applying more or less energy to the boiler and this recipe may benefit from being run fast. Spirits defined by their fatty acids and esters like brandy and whiskey benefit from slow distillations with longer time under heat while gin botanicals, in particular juniper, benefit from faster distillations and less time under heat. With juniper and many other botanicals, heat changes the nature of the terpenes which define their aroma. Changes in juniper due to heat can be both favorable and unfavorable, but because our gin has already seen heat once when it was initially distilled, it probably would not benefit from too much more. There are studies that explore the changes in juniper when subject to the heat of distillation, such as the paper that supported the patent for Oxley gin’s vacuum distillation process, but be aware, some of the papers are red herrings written to support a patent. We can learn from these papers, but we have to consider their biases and what they leave out.

The limitations of re-distilling gin with an extra botanical need to be pointed out. Where spirits like whiskey & rum have cuts made to reduce congeners like ethyl acetate and acetaldehyde, gin has cuts made to reduce congeners like excess terpenes that can cause cloudiness. The terpenes of the gin have already been cut and optimized for clarity, but the newly introduced botanical has yet to be cut. If the cuts are made to reduce terpenes in an introduced element like the Tabasco, they risk damaging the integrity of the gin upon redistillation therefore co-distillation with the original botanical charge is always the preferred option. None of these concepts should deter anyone from experimenting, but they do place limits on re-distillation that distillers should be aware of.

The aromas in this recipe illustrate an interesting phenomenon in sensory science. The capsaicin in the chilies, which lends piquancy, is not volatile and is separated due to the principles of simple distillation just like the salts. The distillate may still seem somewhat piquant due to sensory convergence or what is sometimes also called non-linguistic contrast detection. All our prior experience links the aroma of chilies with piquancy so that is how we categorize the aroma and this parallels the phenomenon of categorizing colors as warm & cool. Unique divergent scenarios which distillation makes possible, where olfaction anticipates other sensations that do not arise, can be quite fun.

RECIPE

75 mL Tabasco
500 mL dry gin (Seagram’s)
250 mL water

To neutralize the acetic acid in the vinegar, add 5.25 grams of baking soda per 75 mL of Tabasco. Be patient and add the baking soda slowly because the acid/base reaction which forms the non-volatile salts will cause a lot of foaming due to the release of CO². Complete neutralization of the acid can be confirmed with a simple pH testing strip or organoleptically by trusting your nose. Neutralize the Tabasco before adding it to the gin because a smaller volume is much easier to handle.

Mix the ingredients and re-distill together on high reflux until the thermometer on the still reads 93.33°C. Going past 93.33°C may result in a cloudy distillate and or unpleasant cooked aromas. The extra water is added to reduce the chances of solids in the Tabasco falling out of solution and scorching on the bottom of the boiler. Scorching happened once while developing the recipe and it was like a tear gas bomb going off in the house; our eyes watered for hours. With care, scorching is easily avoided.

Failure to completely neutralize the acetic acid can result in a distillate with a bluish tint from mildly poisonous copper acetate. Copper acetate salts are produced by the corrosion of the copper in the condenser from the acetic acid. Do not drink the distillate but rather learn the lesson and start again.

Using your hydrometer re-cut the distillate to your desired proof with distilled water (recommended proof 80-90).

COCKTAILS

Tabasco aromatized Negroni

1 oz. Tabasco aromatized gin
1 oz. sweet vermouth
1 oz. Campari

Corpse Reviver No. 2.1!

.75 oz. Tabasco aromatized gin
.75 oz. triple-sec
.75 oz. Lillet
.75 oz. lemon juice
bar spoonful Absinthe

‘Since 1886’ (we’ve been adding Tabasco to everything…)

1.5 oz. Tabasco aromatized gin
.75 oz. triple-sec
.75 oz. lime juice
dash Angostura bitters

Bees Knees

1.5 oz. Tabasco aromatized gin
.75 oz. honey syrup (1:1)
.75 oz. lemon juice

This last cocktail recipe synthesizes the character of the famous strawberry tree honey of Corsica, Sardinia, and the Al Garve in the south of Portugal. The fruit of the strawberry tree has an aroma redolent of chilies that comes through in the honey as well as in the famous Al Garve moonshine called Medronho. Medronho (which unfortunately is slowly going extinct) is made from the fruit of the strawberry tree.

8 thoughts on “Distiller’s Workbook exercise 1 of 15

  1. What is the effect on the neutralized Tabasco, as is? Is distillation the only, or merely the best, means of winnowing out the resulting salts? In other words, can I apply neutralized Tabasco without a still?

  2. distillation both separates the salts and separates compounds that contribute to piquancy. so the resultant distillate smells hot but does not taste hot. so I don’t think you can do much without a still. centrifuged tabasco is pretty cool and loses a fair amount of its piquancy to the sludge that is separated.

  3. When you say:
    “Spirits defined by their fatty acids and esters like brandy and whiskey benefit from slow distillations with longer time under heat while gin botanicals, in particular juniper, benefit from faster distillations and less time under heat.”
    Can you elaborate on that? Where are you getting information that one botanical/ester benefits from slow or fast distillation? Is there a reference source that list various botanicals with ideal times under heat?

  4. Hi R.

    Fatty acids benefit from time under heat because it increases the probability they will become esters which reduces their volatility and makes them more likely to appear in the distillate. Time under heat also benefits carotene derived aroma and invests in the beneficial transformation of dunder/stillage so it can be recycled back into the next ferment. Time under heat however has to be justified and the target congeners have to be present.

    Botanicals often have terpene based aroma and under extended time under heat, certain types can degrade into more ordinary forms. This is the reason many gins explore partial vacuum or sometimes even full vacuum. There are not many research papers on gin because its production was not generally considered an agricultural topic. I link to a few papers in other posts. To understand the aroma of a single botanical you can do trial distillations using tools like the birectifier. The first and most volatile fractions feature terpenes that are most susceptable to heat and oxidation. For gin distillation, where botanicals are co-distilled together, juniper often becomes your limiter. Certain botanicals like Jasmin are known to be heat sensitive. For gins, a lot of this is just theory and the magnitude of the effect in practice may not be make or break. I personally do not believe vacuum is necessary to produce a successful gin, especially because it is so expensive.

    I hope that helps. Best. -Stephen

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