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.