Mash Bill – Bourbon and Whiskey Ingredient Guide

Mash ingredients - Whiskey, Bourbon

If you’re relatively new in your distilled spirits journey, you may find yourself hearing a lot about mash bills. There is much debate in the world of whiskey about which type is the best, and it’s something the dedicated bourbon fan may feel strongly about. But what are they — and how do they affect the flavor profile of the finished product? 

The mash bill is the list of grain ingredients used during fermentation. In this post, we’ll learn all about them. We’ll discuss the benefits of each grain, how they have been used by whiskey makers over the centuries and the historical reasons different parts of the whiskey world evolved their own unique spirits.


To make whiskey, we must first make beer.

Our ancestors learned long ago that certain grains could be combined with water and — with a bit of luck and patience — turned into alcohol. In fact, brewers in the cradle of civilization were making beer as long as 7,000 years ago!

When the art of distillation reached the beer-drinking regions of the world, people found out they could create a wonderful new spirit by distilling fermented grain mashes — basically beer without hops. To better understand how these early distilled spirits became the whiskey categories we all know and love today, let’s take a look at each of the grains and how they contribute to the overall flavor.  

Consider this section as an ode to the Poaceae family of grasses.

Corn, rye, wheat and barley are all included in this family tree and make up the main ingredients of most whiskeys. When you add another Poaceae grass — sugar cane — to the equation, the list of beverages that owe their existence to these plants is quite impressive: beer, whiskey, rum, sake, baiju and many more.  

Malted Barley

Malted barley is the mother of all grains.

Barley’s Latin name Hordeum vulgare. There are two-row and six-row varieties as well as spring and winter barley types. Two-row barley is preferred by many distillers because it has more of the enzymatic action. That allows more starches in the grains to be converted to sugars, which then leads to mashes with higher pre-fermentation BRIX readings, which in turn will result in beer with higher alcohol contents.

Malted barley is used for the enzymatic conversion of starches to sugar during the cooking of the mash. It gives the resulting whiskey many associated roasted-toasty flavors, an oft-described nutty quality. And peat smoke used during the malting process gives peated whiskeys their flavor.   


Although they evolved on separate continents, corn (Zea mays) and malted barley are evolutionary cousins. To a writer, this seems a fitting analogy to the origins of bourbon — a marriage of whiskey-making traditions from Europe and America.

Corn is the primary grain in bourbon production and is what gives the liquor its sweetness.

For the longest time, distillers worked with corn as a commodity. No. 2 Dent corn (Zea mays indenta) was used to produce most Bourbon whiskey. However, a lively debate between distillers has occurred regarding whether terroir may apply to distilled spirits in the same way it does wine. Today, distillers are experimenting with all types of native and heirloom corn grains, including Whapsie Valley and blue corn varieties. 

Like a bite of summer corn on the cob, the use of corn grain in the mash bill adds a touch of sweetness to the whiskey. 


Rye (Secale cereale) is notoriously difficult to turn into whiskey. Rye’s starches are harder to convert to sugar. Mashes are temperamental. And the elasticity of high-grain mash bills can cause foam-over during distillation — when mash foams over the pot and into the still head to cause general havoc with the rest of the system.

In Europe, where wheat and barley were plentiful, rye was not traditionally used in whiskey production. Rye has relatively low yields, is inedible to most livestock and challenging to work with for brewers and bakers alike. But travelers to the New World — especially in the cold, harsh climates of New England and Canada — appreciated the hardiness of the winter-resistant rye grain. So, when they had access to any extra grain after harvest, it went into the mash.

As a result, the use of rye in whiskey is a uniquely North American phenomenon.

Rye is a common ingredient in both bourbon and Canadian whiskeys. American Rye whiskey must contain at least 51 percent rye grain in the mash bill and be aged in new American charred oak barrels.

Rye grain is known for giving bourbon and other whiskeys a robust, spicy character. 


Wheat’s Latin name is Triticum aestivum. What makes wheat great as a food source makes it less than ideal for brewers and distillers. Tightly packed proteins in the grain make the starches less accessible to conversion into edible sugars for the yeast. But its prolific stature as a food crop meant that it was often a plentiful source of excess grain come harvest time.

Wheat was used throughout the history of whiskey in different proportions. But it was the invention of the column still that led to its prominence in Scotland and Ireland. There, column-distilled grain whiskey made from corn, wheat or some combination of the two was produced and often blended with malt whiskey to make blended whiskey. The decision to use corn or wheat was often tied to grain prices on the commodities market.

Wheat is known for its mellowing effect on the resulting whiskey. Whiskeys that utilize this grain are often said to have a soft mouthfeel along with a smooth and mellow finish. 

Exotic Grains

Today, distillers are experimenting with flavors from ‘exotic’ grains like sorghum, quinoa, rice, buckwheat. From small craft distilleries using local crops to regional brands like Corsair to big names like Jack Beam, many innovative production teams develop new whiskey flavors with these non-traditional grains.

Mash Bills by Whiskey Type

Now that we understand what each grain brings to the table, let’s check out what you can expect from each category’s mash bill. All whiskeys are made from 100 percent grains. But you’ll see that the grains you use during the mashing process have a big impact on flavor.

[RELATED: Types of Whiskey]

Bourbon Mash Bill Types: High-rye vs. Traditional vs. Wheated bourbon whiskey

Bourbon is a product category native to the United States that is also protected by international trade agreements. By law, a bourbon mash bill must contain at least 51 percent corn. But that leaves up to 49 percent, which can consist of any combination of grains the whiskey maker chooses.

To better describe the significant differences these combinations can have on the finished flavor profile, whiskey distillers have come up with some terms to describe approaches to bourbon making. It should be noted that these terms are not regulated. While a whiskey must contain 51 percent corn to have the word bourbon on the label, the same product can use the term high-rye regardless of the proportion of rye grain in the mash bill. For example, Wild Turkey has a mash bill of 75 percent corn, 13 percent rye and 12 percent malted barley but has the term ‘high rye’ on its packaging.

Some examples of high-rye bourbons include Bulleit (28 percent rye), Old-Grandad (27 percent), FEW (20 percent), Woodford Reserve (18 percent), Old Forester (18 percent) and I.W. Harper (18 percent). An interesting product to consider is Four Roses, which blends barrels of four separate mash bills for each batch, including 35 and 20-percent rye mashes. 

[RELATED: Rye vs Bourbon whiskey]

The term ‘traditional bourbon recipe’ takes on a lot of weight in the whiskey world. It can mean different things to different distillers. The lack of industry standards regarding the term leaves a lot of room for interpretation by distillers — or marketing teams. We hesitate to wade into this controversy, but inquiring minds want to know…

In general, a traditional bourbon recipe has about 75 percent corn, with the remainder more or less divided between malted barley and rye grain. Examples of traditional bourbon mash bills include George Dickel Tennessee Whiskey (84 percent corn), Michter’s (79 percent), Elijah Craig (78 percent), Heaven Hill (78 percent), Ezra Brooks (78 percent), Jim Beam (75 percent), Baker’s (75 percent), Basil Hayden’s (75 percent), Booker’s (75 percent) and Knob Creek (75 percent). 

We should note that Buffalo Trace does not disclose their bourbon mash bill.

Finally, the term ‘wheated’ bourbon describes a product that replaces rye grain with wheat to offer a smooth and mellow whiskey. Examples of wheated bourbons include Maker’s Mark, Larceny, Old Fitzgerald, Weller and Van Winkle.

Rye whiskey vs. Canadian whiskey Mash Bills

Much ado about rye.

There is a lot of confusion among newcomer whiskey fans regarding the terminology around the word ‘rye.’ In addition to confusion about high-rye bourbon, in the United States’ rye whiskey’ describes a specific product type, while in Canada any type of whisky can carry ‘rye’ on the label if it has even a tiny bit in the mash bill.

American Rye whiskey must use a mash bill that contains at least 51 percent rye grain. 

Some popular rye whiskeys include Old Overholt, Rittenhouse Rye, Pikesville Rye, Wild Turkey Rye, Jim Beam Rye and many other bourbon-brand extensions.

Canadian blended whisky often combines whiskies with different mash bills — some with extremely high percentages of rye and others with zero rye grain. One product, Alberta Premium 100% Rye was named world whiskey of the year in Jim Murray’s 2021 Whisky Bible. It is made from 100 percent rye grain and originally started out as a ‘flavouring’ whiskey for the popular Canadian Club brand.

Scotch single malt vs. Irish copper pot vs. Blended malt mash bills vs. American malt mash bills

There is a reason malted barley is such a revered grain. Without it, yeast wouldn’t be able to ferment grain, brewing would never have been possible and the world would be left with only wine to drink. *shudders* 

As a result, the earliest whiskey cultures used malted barley primarily or exclusively in their grain bills. This allowed for maximum alcohol content in the resulting beer, which led to higher alcohol strengths in the distillate. 

Single malt whiskey requires the mash bill to contain 100 percent malted barley. While Scotland is synonymous with the term single malt, Ireland also has a long tradition. There are at least 130 distilleries in Scotland making single malt whisky, and an example of a well-established Irish Single Malt is Knappogue Castle.

Irish single pot or pure pot is a style of whiskey that has a long history and has benefited from a recent resurgence. Single Pot whiskey has a mash bill that is a combination of malted and unmalted barley grain. The unmalted barley gives the whiskey a rich and complex character. Examples of well-known single pot whiskeys are Redbreast, Green Spot and Yellow Spot. 

Blended malt whisky is a sub-category of scotch that also has a rich history. Until the 1980s, it was more often referred to as vatted whisky. Blended malt whisky products blend barrels of single malt whiskies produced at separate distilleries together. Examples include Johnnie Walker Green Label and Peat Monster from Compass Box.

[RELATED: Scotch vs Bourbon]

Finally, a wide range of American distillers are beginning to experiment with the flavors of malted barley mash bills. Unlike Ireland and Scotland, the United States does not recognize single malt as an independent category. However, ‘Malt Whiskey’ is a product that contains at least 51 percent malted barley in the mash bill. Popular products in the American Malt Whiskey category include Westland and Stranahan’s whiskey.

[SEE ALSO: Bourbon vs Irish whiskey]

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