What are the common types of grains used in a bourbon mash bill?

The common types of grains used in a bourbon mash bill are indeed corn, rye, barley, and wheat. This selection aligns with the legal requirements for bourbon production, which must contain at least 51% corn to qualify as bourbon. Corn is the primary grain used due to its natural sweetness, which contributes to the rich flavor profile of the bourbon.

Rye is often included in the mash to add spiciness and complexity, while malted barley provides essential enzymes that help convert starches into sugars during the fermentation process. Wheat can also be used in varying amounts to create a softer, smoother taste, resulting in a more approachable bourbon.

The other choices include grains that are not typically associated with bourbon production. Rice and oats, for example, are more common in other types of spirits or beers, but do not meet the traditional guidelines for bourbon mash bills. In addition, millet and grain alcohol also do not play a role in the production of bourbon, which further underscores the accuracy of the correct answer in recognizing the essential components that define bourbon.