Mash bill bourbon is a type of American whiskey that is made from a mash of at least 51% corn. The other grains used in the mash bill can vary, but they typically include rye, wheat, and malted barley. Mash bill bourbon is typically aged for at least two years in new, charred oak barrels.
The mash bill is an important factor in determining the flavor of bourbon. A higher percentage of corn in the mash bill will result in a sweeter, smoother bourbon, while a higher percentage of rye will result in a spicier, more robust bourbon. Wheat and malted barley can add a variety of flavors and aromas to bourbon, depending on the proportions used.