Bourbon Mash Bills Explained

What a mash bill actually is

Distilleries cook grain with water, let yeast eat the sugar, and then distill what is left. The percentages of each grain in that cook is the mash bill. It is usually written as three numbers, like 75 percent corn, 13 percent rye, 12 percent malted barley. Some distilleries publish theirs. Plenty do not, and you end up piecing it together from interviews and enthusiast spreadsheets.

Corn has to be the majority because that is the law. If you want the rest of the legal picture, read what makes bourbon bourbon.

Corn: the sweetness and the body

Corn is cheap, it is loaded with starch, and it distills into something soft and sweet. Think corn bread, caramel, and a rounded mouthfeel. Push the corn higher, up toward 75 or 80 percent, and the whiskey gets sweeter and simpler in a way that can be very easy to drink. Push it past 80 and you are heading toward what some people call a corn forward or high corn bourbon, where the grain sits right up front.

Rye: the spice

Rye is the grain that gives bourbon its bite. Black pepper, cinnamon, mint, sometimes a dry herbal edge. Most standard bourbons run somewhere around 8 to 15 percent rye, which is enough to keep the sweetness from getting flabby without taking over.

A high rye bourbon usually means roughly 20 to 35 percent rye. Those pours taste spicier and drier, and they tend to hold up better in a cocktail because the spice cuts through vermouth and bitters. If you have ever wondered why one Old Fashioned tastes flat and another tastes alive, the rye percentage is often the reason.

Wheat: the soft one

Swap the rye for wheat and you get a wheated bourbon. Wheat does not add much flavor of its own, so it gets out of the way and lets the corn sweetness and the barrel do the talking. The result is softer, rounder, and often described as bready or gentle. Wheaters have a devoted following, and a few of them are among the hardest bottles in the country to find at shelf price.

If you are new and you find high proof rye heavy bourbon harsh, a wheated bourbon is usually the friendlier place to start.

Malted barley: the quiet worker

Malted barley is almost always the smallest slice of the mash bill, often 5 to 12 percent. It is there because malting activates enzymes that convert starch into fermentable sugar. It contributes a light biscuit and nutty note, but mostly it is there to make the process work.

How to use this at the shelf

• Sweet and easy tonight? Look for high corn or a wheated bourbon.
• Making cocktails? A high rye bourbon will not get lost.
• Tasting side by side with friends? Pick two bottles that differ only in the number two grain. That single comparison teaches more than reading about it.

The mash bill is not the whole story. Proof, barrel entry, warehouse position, and age all pile on top of it, and proof in particular can make the same recipe feel like a different whiskey. Two bottles can even share a mash bill and land in completely different places, which is part of why single barrel and small batch releases vary as much as they do.

Start paying attention to the grain recipe and you stop buying bottles at random. You start buying the kind of bourbon you already know you like.