Mashbill is a term used in the production of whiskey to refer to the mixture of grains used to make it. The mashbill determines the flavor, aroma, and body of the whiskey. Different distilleries use different mashbills, which is one of the factors that makes each whiskey unique.
The most common grains used in mashbills are corn, rye, wheat, and barley. Corn is the most commonly used grain in bourbon whiskey, while rye is typically used in rye whiskey. Wheat and barley are often used in smaller amounts to add flavor and complexity.