First, some disclosure: for the second year in a row I've been given tickets to this event from the fine folks at the Madison Malt Society. In exchange, I print some press releases and generally help them to raise awareness for the event and for fermented and distilled malt beverages. While this piece is certainly, in some ways, an advertisement for the event (occurring tomorrow, Thursday, February 18th at 7pm at the Edgewater Hotel), its genesis was more in my own curiosity surrounding these beverages; this disclaimer was more of an afterthought than an attempt to sit down and right an advertising piece for them. So, with that said, thank you to Madison Malt Society and I hope you, the fine reader, learn a thing or two.
Just some of the beverages made from malted grains:
- bourbon (corn)
- whiskey (any grain)
- scotch (barley)
- rye (rye)
- vodka (grain-neutral)
- gin (grain-neutral)
- akavit (aka "aquavit", grain-neutral)
- absinthe (grain-neutral)
Obviously, we can split these into two main categories: whiskey/whisky and grain-neutral. In the case of whiskey, it is distilled to 80-90% alcohol in order to retain some flavor of the base grain. Grain-neutral spirits are distilled between 90-95.6% alcohol, then, often flavor is added through any number of processes. As a side note: above 95.6% ethanol and water are an azeotrope.
Whiskey is a general term used to describe any grain-based distilled product that is not not grain-neutral (yes, technically, vodka/gin/absinthe/etc are not entirely grain-neutral, but for these purposes we'll throw them together as "non-whiskey" and cross that bridge when we get to it). This means that the whiskey retains some flavor of the base grain. Bourbon for example, has a grain-mix of at least 51% corn. Rye, at least the American version, is at least 51% rye.
In fact, we can break "whiskey" down into "single-malt" and "everthing else". Single-malt whiskeys are whiskeys that have only one type of malt in their grain profile. While not uncommon, they are the exception to the rule, particularly in the United States. But, within "Single-malt" we do find the occasional rye whiskey, but more usually it is Scotch. So, what is Scotch? The Scotch Whiskey Order of 1990 spells it out:
2. produced at a distillery in Scotland
3. from water or malted barley (no adjuncts)
4. processed at that distillery into a mash and fermented by only adding yeast
5. less than 94.8% ABV
6. Matured in oak casks smaller than 700 litres (approx. 184 gallons or 6 bbls) for not less than 3 years
7. No substance other than water or "spirit caramel" (a coloring additive) has been added
So, what is a product that meets all of those requirements except #2 (made in Scotland)? Whiskey. Indeed, many of the whiskey types have very strict rules. Indeed Federal Regulations, 27 CFR 5.22, set out the specifics for a variety of distilled spirits.
Neutral-grain spirits, such as vodka and gin, are made using grain-based mashes but are distilled to the point where all, or most, of the flavor has been removed. It is then cut with water to the desired alcohol level. These can then be flavored in any number of ways. For example, neutral-grain flavored with juniper and other botanicals is "gin". If spices such as caraway, or anise, or cardamom or fennel are used it can be "akavit". Though many American producers still just call it "vodka" because consumers know what "vodka" is, and have never heard of "akavit" or "aquavit".
It is interesting to note, or maybe specifically point out, that in all of these cases, there is very little difference between a grain mash that gets fermented and turned into beer and a grain mash that gets fermented and distilled into spirits. Thus, it shouldn't be much of a surprise that more and more breweries are starting to take on some interesting side-projects. Rogue Brewery in Oregon makes a fantastic whiskey, New Holland Brewing in Michigan makes an excellent gin, Dogfish Head in Delaware makes an amazing chocolate vodka (and I don't like chocolate or vodka).
So, given that the only difference between beer and vodka is distilling, how does distilling work? The answer is more complex and scientific than I could even begin to explain in any amount of detail. But the gist of it is this:
- pot distillation: also called "batch distillation": a large onion-shaped kettle is fired causing the liquid (basically, beer), called "wash", to boil; the vapor produced from the boiling contains a higher-concentration of alcohol, and is routed through coils to cool to form a low-alcohol liquid (about 25% ABV or so). This first-distillation is then boiled again to create a high-alcohol liquid. At this point, if it is above 90% ABV, it would be filtered and called "vodka", if below 90% it is aged in oak barrels, where it gets its dark color, and called "whiskey"
- column distillation: also called "continuous distillation" consists of two vertical columns. The first column has a series of steps where liquid, wash, can condense; this condensed liquid is recirculated through the second column until the proper alcohol percentage is reached. The condensation at the highest point of the column is highest in alcohol concentration.
Lew Bryson had a fantastic article in Ale Street News about microdistilling that is a must-read for anyone interested in getting into these beverages. One, ummm..., brewing controversy is the use of pot stills v column stills. The big-guys almost universally use column-stills, the little guys almost universally use pot-stills. Lew does a great job of unpacking that discrepancy. There's also some controversy over using pre-made grain-neutral spirits and simply adding your own aging or flavoring additives.
Here in Wisconsin, breweries can't also be distilleries. However, Capital Brewery, in Middleton, does make the mash for many of the Wisconsin-based distilleries. So, head on over to the "Celebration of American Distilling", try some samples, talk to some of the master distillers and find out what these drinks are all about.