Mash Bill
A mash bill is the specific grain recipe used to produce a whiskey or other grain-based spirit, expressed as percentages of each grain type, which is a key determinant of the product's flavor profile and regulatory classification.
In Plain English
A mash bill is the recipe for the grains used to make whiskey. It lists the percentages of each grain — corn, rye, wheat, malted barley, and other grains — that go into the production process. The mash bill is what separates different whiskey styles. Bourbon must be at least 51% corn. Rye whiskey must be at least 51% rye. Wheat whiskey must be at least 51% wheat. Beyond those minimums, distillers craft their own specific ratios to achieve their desired flavor. A bourbon with 75% corn, 15% rye, and 10% malted barley will taste quite different from one with 60% corn, 36% rye, and 4% malted barley, even though both legally qualify as bourbon. Mash bills are sometimes public marketing information and sometimes closely guarded trade secrets.
Technical Detail
The mash bill determines the product's standard of identity classification per 27 CFR 5.22. Bourbon requires 51%+ corn, rye whisky requires 51%+ rye, wheat whisky requires 51%+ wheat, and malt whisky requires 51%+ malted barley. Corn whisky requires 80%+ corn and has different barrel requirements. The remaining percentages are filled with "small grains" — typically combinations of rye, wheat, and malted barley. Malted barley provides enzymes for starch conversion during fermentation, so it appears in most mash bills at 5-15%. The mash bill affects not only flavor but also fermentation characteristics, yield, and aging behavior. Distillers may use the same mash bill with different barrel treatments, age statements, or proof points to produce different products.
Why It Matters
Mash bills are central to whiskey marketing and product differentiation. For ingredient suppliers and grain companies, understanding which grains are in demand based on whiskey production trends is valuable market intelligence. For market analysts, tracking which mash bill styles are trending (high-rye bourbons, wheated bourbons, etc.) reveals consumer preference shifts. For compliance consultants, ensuring the mash bill supports the claimed standard of identity is a key validation step.
Related Terms
Frequently Asked Questions
Do distillers have to disclose their mash bill?
No. The TTB does not require mash bill percentages to appear on the label, only the class/type designation (which implies the dominant grain). Some distillers share their mash bills as marketing, while others keep them proprietary. The actual percentages are part of the production records maintained at the DSP.
Can a distiller change their mash bill?
Yes, but changing the mash bill may affect the product's flavor profile and potentially its classification. If the change results in a different standard of identity (for example, dropping below 51% corn would disqualify a bourbon), a new COLA would be needed with the correct classification.
What is a "wheated bourbon"?
A wheated bourbon uses wheat as the secondary grain instead of rye. The mash bill is still 51%+ corn (as required for bourbon), but the remainder includes a significant wheat portion. Wheated bourbons tend to be softer and sweeter than high-rye bourbons. Famous examples include Maker's Mark and W.L. Weller.