How Spirits are Made
Spirits are the product of distilled fermented beverages, such as wine and beer. So if you distill wine and beer, you will get brandy and whiskey, respectively. There are several categories of spirits, the biggest ones are gin, rum, whiskey, vodka, tequila, and brandy. What differentiates one from another is the base ingredient and the specific production methods used to make it.
Those particulars are covered each spirit category's individual section (which I'll be adding in the coming months). Here, we’re taking a broader view of spirit production, and the different tools and techniques that may be employed to shape them.
There are three primary stages of spirit production: fermentation, distillation, and post-distillation. This section contains a page focussing on each stage (post-distillation is split in two), which are linked to through the images below. These will help to put all the details covered on the individual spirit category pages in context, with the ultimate goal of helping you make better and more informed decisions at the liquor store, and thus better cocktails.
ABV vs. Proof
ABV and proof are two measurements used to denote how much alcohol a spirit (any alcoholic beverage) is, and they essentially are the same.
ABV, Alcohol by Volume - This is the most common metric used. It refers to the percentage of a beverages volume is alcohol. So 40% ABV means that 40% of that bottle is alcohol (aka ethanol) and 60% of it is water and congeners. Alcohol used to sometimes be measured by weight as well, which would be labeled as ABW, though that is not as common anymore.
Proof - A spirits proof is simply double it’s ABV. It is expressed in degrees, so 40% ABV is 80º proof, 50% ABV is 100º proof, and so on. It is more common on labels in the U.S., and while it's somewhat redundant as a measurement, the term "proof" is widely. People often describe something is high or low "proof".
Why is it Called Proof?
Proof used to mean something different than ABV. Initially, when the term It was conceived in England, proof measured the alcoholic density, or specific gravity, of booze, relative to its water content. On that scale, 100 proof equaled about 57% ABV.
This used to be measured by a test that involved soaking gunpowder with booze. If the booze was 57%, the gunpowder would still light. So if it ignited, that was "proof", that the booze was 57%, aka "at proof". Naturally, this test has been since replaced by more accurate (and less fun) methods of measuring alcohol strength.
But in its day, this gunpowder method of ensuring the strength of booze was very important for taxation purposes, as well as for ships that were carrying spirits, which was one of their primary means of transportation through the 16th and into the 20th century. Spirits traveling by sea were often required to be "at proof", which is why today spirits that are 57% ABV are known as “navy strength”. You will still find navy strength gins and rums bottled at 57% ABV, or 114 proof by today's measures.
The modern definition of proof is a descendant of a separate system developed in the United States in the 19th century which was based on alcohol percentage from the beginning, just using the word proof. As far as I can tell, proof is only printed on labels today out of tradition. That, and for the fact that 100 proof sounds way cooler that 50% ABV.
Geographic Indications and Designations of Origin
Many styles and categories of spirits possess a Geographic Indication (GI), meaning they can only be made in a particular country or region. For example, Cognac is a brandy that must be made in the delimited "Cognac region” of France, tequila must be made in Mexico, and bourbon must be made in the United States.
A common subcategory of GI is a Designation of Origin (DO). These are based on more the concept of terroir, meaning some facet of the surrounding environment, be it the soil, climate, water source, etc., contributes defining characteristics to the spirit that would be inimitable elsewhere. These also often include production guidelines. Broadly speaking, the difference is philosophical. A Geographic Indication simply protects a country/regions right to their intellectual property, whereas a DO insinuates that property would be impossible to replicate elsewhere. They are meant to ensure quality and maintain the integrity of the property itself. But the lines of truth here can be gray, more on that below.
Appellation O'origine Contrôlée (AOC)
Countries have their own internal systems and titles (often it’s simply Designation of Origin in their native language) that govern these certifications. Globally, they are all presided over by the World Trade Organization (WTO). One of the best-known examples is France's Appellation d'origine contrôlée (AOC) system, aka “Controlled Designation of Origin”. It originated in the 1400s and set the benchmark for many of the DO systems that exist today. A vast array of French products are protected under an AOC. In addition to location restrictions, they also contain highly detailed specifications on production which are forcefully upheld. Cognac, Armagnac, Calvados and Agricole Rhum from Martinique are all spirits that possess AOCs.
Why is all this important you ask? Because it often the best way parsing out the differences between spirit categories and styles, even if it's purely technical. This is especially great for nerds like me who is obsessed with classifying everything.
GIs and DOs Aren’t Everything
Keep in mind, since each country has a different system, the standards are not all the same. This is particularly true of DOs. For example, in Mexico, but only 9 states have a DO that allows them to make an agave spirit labeled as Mezcal, though fantastic Mezcal is made all throughout Mexico, even if it can't be labeled as such. The reason for this has more to do with bureaucracy than terroir. This is all to say, the lines between these Geographic Indications can be blurry.
On that note, remember that while these systems can be helpful and often raise the bar for many categories, there’s no certification for quality. Just because something is made in a certain place in a certain way doesn’t make it better. Nor does the fact that it was made somewhere else make it bad. Take Japanese whisky, it was created in the 1930s in the image of scotch, and for decades was dismissed as a cheap imitation. But in the last 25 years, Japan has come to be recognized for making some of the best whisky in the world. Keep an open mind. Labels aren't everything.
Ethanol: The Alcohol for Drinking
Chemically speaking, when one speaks of alcohol, it is referring to a class of chemical compounds including isopropanol, methanol, and ethanol. But in the context of beverages, when we say alcohol, what we’re specifically talking about is ethanol, aka common alcohol. Ethanol is the best tasting, easiest to process and safest alcohol for human consumption. There are a few other alcohols that factor into booze-making, such as methanol, but ethanol is what we’re really after.
The Base Ingredients of Major Spirits
Whiskey: Grain, typically barley, corn, wheat or rye.
Gin: Usually grain, but can technically be anything. It's also infused with an assortment of botanicals, particularly juniper.
Vodka: Usually grain, can be anything, potatoes, for example.
Rum: Sugar cane - usually in molasses form, but sometimes fresh cane juice of syrup.
Tequila & Mezcal: Agave
Brandy: Most commonly grapes, which are used for Cognac and the majority of aged brandies, but technically brandy can be made from any kind of fruit, in which case it will be called "apple" brandy, "apricot" brandy, "pear" brandy, etc.
Several other elements have an influence on the final product including the barrel's size, shape, condition, the species of oak, and the surrounding climate.
General Spirits Information
Here's some general information that doesn't apply to spirit production directly, but it is key to understanding it. There's also some good info you may encounter when reading a liqour label.
The chemical structure of ethanol: CH3CH2OH
The Stages of