bourbon mash bill

There are a variety of things that affect the flavor of bourbon. These include the storage temperature, the time it is aged, and the bourbon mash bill. Bourbon flavor can range from really sweet to incredibly spicy, and from super smooth to overly sharp. That being said, the one thing that has the greatest effect on the taste of the spirit is the mash bill.

A bourbon mash bill is basically the percentage of different grains and how they fit together in a specific bourbon recipe. Different grains provide different levels of spice, sweetness, and smoothness. Exploring different bourbons and then understanding their mash bills will help you choose bourbons that will suit your palate.

When considering what type of bourbon to purchase in the store, or what to use for a specific cocktail, do a little research on the mash bill. It will help you to choose one that fits your style and your taste preferences. Do you prefer sweet? Spicy? Smooth? Here’s how to break it down:

Basics of a Bourbon Mash Bill

In a nutshell, bourbon is crafted from four grains that are essential to the process:


Each grain contributes a slightly different flavor to the bourbon’s profile. Most distilleries categorize their mash bills as “low-rye,” “high-rye,” and “wheated.” They focus specifically on the rye because it adds the spice element.


Corn is the base ingredient in all bourbons. By law, bourbon must be fermented from at least 51 percent corn (amongst other requirements) in order to be called bourbon. Corn makes the bourbon sweet, but the corn flavor itself fades away during the aging process. The longer it ages, the less corn you taste.


Rye gives bourbon its spicy flavor. When some people describe a bourbon as “spicy,” they are only referring to the heat and strength of the alcohol. Conversely, when you characterize a bourbon as “spicy” because you taste baking spices such as nutmeg, cinnamon, allspice, and anise, you are referencing the rye. High-rye bourbons tend to be very spicy, while low-rye bourbons are a bit sweeter.


Many distillers choose to use wheat for flavoring instead of rye. Wheat will mellow the flavor out, taking away some of the spice and heat from the rye and the alcohol. Wheated bourbons were first made famous by Pappy Van Winkle and carry flavor notes of toffee and vanilla.


The most underrated and overlooked grain in the mash bill is Barley. Barley is present specifically for its ability to convert starches to sugar, which helps in the fermentation process and in the flavoring of the bourbon itself. It is used heavily in scotch, but not as much in bourbon.

Percentages of a Bourbon Mash Bill

There are arguably countless mash bills because they are made up of percentages of each grain.  But for our purposes, we are going to narrow it down to three categories:

High Rye

These three recipes can basically encompass all of the different bourbon mash bills on the market today. Bourbons made from these different mash recipes will have distinct tasting notes and different noses. And when you change up the aging times, the possibilities are endless.

Traditional Bourbon Recipe

A traditional recipe might contain around 70-80 percent corn, although the “legal” requirement is 51-79 percent. This gives it a rich, sweet taste that many people associate with a traditional bourbon. When it hits the back of your tongue, it activates your senses and really comes alive.

High Rye Bourbon Recipe

A high-rye recipe of 18 percent or more rye will have a deeper flavor than just corn can offer. The rye adds spice and takes the sweetness down a notch. The barley content will essentially stay the same, as it is needed for conversion of starch to sugar.

Wheat Bourbon Recipe

The wheat recipe is similar to the traditional recipe. It removes the rye, though, and replaces it with wheat at 18 percent or more. The wheat allows the sweetness of the corn to come through. It also magnifies the sugars from the barrel, so you get a sweeter and more mellow bourbon.

The Aging Process

Besides the bourbon mash bill, the aging process can also have a profound effect on the taste of the bourbon. To be legally considered bourbon, it must be aged in new, charred oak barrels. There is no minimum age for bourbon, but the longer it ages, the more flavorful and smooth it becomes.

Bourbon Barrels

“New charred oak barrels” is an interesting requirement. The “new” part refers to the fact that the barrels have never been used before. Bourbon is aged in white oak barrels that have not been used prior to aging that specific bourbon.

The Char

“Charred” refers to a burning process that every new barrel undergoes before being filled. The white oak must be charred to the point that there is a layer of charcoal on the inside. When the bourbon is placed inside and the barrel is stored for aging, the bourbon will soak into the oak. As it heats and cools during the summer and winter months, it will be pushed back out into the barrel.

The layer of charcoal provides additional filtration to the bourbon and adds flavor and color to the profile.


The length of aging is critically important to the smoothness of a bourbon. But the bourbon mash bill has the largest influence on its flavor profile. Learning what mash bill you prefer will help you to make great choices every time you try a new bourbon.

Do you have a favorite bourbon? Do you know what the bourbon mash bill is? Let us know in our comments.

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