What is whiskey made of?

Every whisk(e)y drinker knows what whiskey is made from: cereal grains, water, and yeast. (And don’t forget what gets added or changed when it is aged in a charred barrel, but the science of whiskey barrels is a different topic.)

Cereal grains

A cereal is any edible part of its grain, from a cultivated grass. The grain is composed of the endosperm, germ, and bran. But which grains are permissible in whiskey?

What counts as a permissible grain?

Wheat, Spelt, Einkorn
Oats – They are in the same biological order, family and subfamily as wheat.
Triticale – A modern hybrid of rye and wheat.

What may not be used?

Distillers may not use pseudocereals if they want their distilled spirit to be legally classified as whiskey.  Examples of pseudocereals are:

Amaranth, buckwheat, quinoa (Amaranthaceae) and chia (Lamiaceae)

What are the borderline cases?


Cultivated and wild rices may or may not be considered permissible. Historically, rice has had no relation to whiskey production.

Further, the list of allowed grains for making whiskey is culturally and historically based. Distillers  (who actually make whiskey) and governments (which tend to regulate such things) haven’t used modern-day scientific classification as a way to determine which grains would or wouldn’t use.

Still, from an evolutionary point of view, rice is closer to wheat and barley than corn is. And corn is definitely considered a grain vis-a-vis whiskey production. So by looking at biological clades (“family trees”) one can reason that if corn is included, then rice should be included.

So if we use cultural and historic traditions and laws, then no, rice wouldn’t necessarily be allowed as a grain in making whiskey. If we allow logical reasoning based on biology to extend the traditional list, then rice would be allowed. And here in the US, the Tax and Trade Bureau (TTB) has been allowing rice to be counted as a grain for whiskey.

Other grains

Millet – In the same biological Order and family as wheat. On the other hand, it historically has no relation to whiskey production.

Sorghum – In the same biological Order and family as wheat. On the other hand, it historically has no relation to whiskey production.

Legally, American TTB regulations are worded in such a way that rice, millet and sorghum may be used.

Other ingredients

Enzymes added to the cereal grains

When making a whiskey made from barley (“malt whiskey”) the barley’s natural enzymes convert complex carbs into simple sugars, which are used in the next step (fermentation) Most whiskeys have a significant amount of barley in the mash bill, so no added enzymes would be necessary. But when making a whiskey that is all corn, the amount of natural enzymes is very low, so it is helpful to add enzymes to kickstart the process. When making whiskey from a pure wheat or rye mashbill, the amount of natural enzymes is so low that a distiller really needs to add extra malting enzymes.

Phenol (the flavor of peat)

People in Scotland would never describe phenol as an ingredient of, or additive to whiskey. The phenol molecule – released from burning peat – is so much a part of their whisky history and culture that it’s considered as natural as breathing. Of course it is there – why wouldn’t it be?  But generally speaking, peat is not found in distilled spirits – both past and present – unless it is added by drying the grains with burning peat. Technically, the phenol molecule is an added flavoring, that merely is so culturally pervasive that people don’t think of it that way.

In many parts of Scotland, distilleries were built in out of the way places because land was cheap. Instead of using burning wood to dry grains, distillers burned local peat because it was readily available and cheap. Over generations people got used to this as being “what whisky should be”, rather than as an phenol-contaminated outlier. To be clear, there’s nothing wrong with this. It has become a time honored tradition, and many (no, not all!) whiskys of Scotland are peated. Some of us have grown to love a peated whisky, while for others, no so much.

pointing finger

Here you can check out our reviews of  bourbonScotch,  Irish whiskey,  Canadian whiskey,  ryes or flavored whiskys.

author blogger me in Maine

And feel free to learn more about me, Distilled Sunshine.


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