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18 May 2019

On Cocktails: If You Like Good Booze, Tip Your Hat to the Wonders of Yeast and Fermentation

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My kitchen counter looks like a biology lab.

Milky water and floating produce sit in jars that burp when I loosen the cap a tiny bit. The smells of cabbage, garlic and onions waft through the air. The sauerkraut, in the largest jar, is diminishing steadily by the day—and the cauliflower giardiniera is being enjoyed as well. The slimy pickles have been a harder sell; they taste, as my chef put it, “Weird.” They’re definitely pickles, but kind of carbonated.

Microorganisms are a crapshoot … what can I say?

My expedition into natural fermentation got me thinking about the less-than-sexy process of making very-sexy booze. You see, I am what they call a “nerd.” Being a bartender hides that a bit, but the craft-cocktail scene is infested with us. Why else would we care about a cocktail from 1879 when vodka-and-soda pays the bills better? Because I am a nerd, I care—and wish others also cared—about how these amazing alcoholic products are made. Liquor companies throw around phrases like “single barrel” or “10 times distilled” or whatever the marketing term of the moment is, but how many actual consumers or bartenders really know how the sausage is made, so to speak?

I am reading Proof: The Science of Booze, by Adam Rogers, which covers everything about alcohol from yeast and sugar to hangovers. Without giving away his tales of the unsung people who contributed to the history of distilled liquor (and you should definitely pick up a copy for your bar library …. wait, you don’t have a bar library?), I thought I would share some of the basics about what goes into making your favorite spirit.

Let’s start with sugar. Most people have heard the terms “malt whiskey” or “malt beverage,” but what does that actually mean? Malting is a process by which grains, often barley, are turned from starch—a form of sugar that yeast can’t eat—into something that yeast can eat. I am going to skip most of the technical jargon here, but basically you trick the grain into “thinking” it should start breaking down its starchy body so it can grow.

Scotch-makers love to brag about their malting floors, where earnest men with shovels and boots turn grain in an old barn. Sure, some (tiny) distilleries actually do that for their entire output. Chances are, however, the Scotch you last enjoyed wasn’t really made that way. Yes, it was malted—at a large industrial operation controlled by one of the major beverage giants. When an American distillery attempted to skip the malting stage using a process created by Japanese scientist Jokichi Takamine, the facility suffered a massive fire, as well as a more-than-suspicious comedy of errors putting it out. As a result, malted grain is here to stay; after all, tradition reigns in the high-end spirits world.

Other spirits—rum, brandy, tequila/mezcal, etc.—that are not made from grain don’t have to worry about this step at all. Makers of cognac and tequila still emphasize the sources of their sugars—limited quantities of grapes and blue agave, respectively, both of which need to be grown in a small region as dictated by law. Some higher-end vodka-makers often market their source sugars, so only rum-makers tend to stay away from glamorizing the humble grass that makes their product … at the moment, at least.

Sugar is just sugar until the magic happens—and that magic comes from yeast. But where does the yeast come from? It’s often already just sitting in the environment ready to go. If you leave wine grapes in a bucket long enough, they will become wine (of a sort). According to various scientists interviewed in Proof, humans may have “domesticated” yeast, just as they domesticated the wine grapes. Perhaps the yeast “used” us too, because as we spread the v. vinifera, we spread the yeasts along with them. The funny thing is the ancients had no real concept of yeast—just that grapes became wine in the way that clouds become rain, or something like that.

Brewers both old and modern use closely guarded strains of yeast that contribute to the specific flavors of their beer—but they always have to worry about getting the right flavors and not letting unwanted yeasts ruin the finished product. These days, strains of yeast are so specific that someone can actually go into a tasting room and try products that are identical, aside from the yeast used. I’ve done this myself at a bourbon distillery, and I can tell you the differences range from subtle to striking. When you buy a “single barrel” bourbon, you’re buying a particular batch with a particular yeast blend, and not hedging your bets on the distiller blending different batches together. It’s a matter of trust that the distiller is choosing the whiskey where the yeast, among other factors, is giving you a flavor profile that justifies the higher price.

What other factors make alcohol taste differently from maker to maker? Many things, depending on the actual spirit. There is the “mash bill” for whiskey, the agave and elevation for mezcal, the barrels used for aged spirits, the actual method of distillation—and a maker is going to put whatever makes the product unique and marketable on the label. Since many get their sugars and yeasts from the same large facilities, the production methods are often what get marketed.

So … what do those pickles on my counter have to do with making all that sweet hooch? The bacteria and yeast in the air that are turning my chilis into beautiful hot sauce also affect the methods that lead to the creation of spirits. While you may not taste the byproducts in the finished spirit in the way that you might in a wine or beer, the fermentation process is still one of the beautiful mysteries of nature. It’s controlled chaos, where we as humanity stumbled for millennia without scientific precision, using our taste buds are our guide. Apparent mistakes can become beloved styles of food or drink as a culture embraces their particular microbes. Maybe my pickles will be next … that is, if I can get anyone to try them.

Kevin Carlow is a bartender at Truss and Twine, and can be reached at This email address is being protected from spambots. You need JavaScript enabled to view it..

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