What primary ingredient is used to distill whiskey?

The primary ingredient used to distill whiskey is fermented grain mash. This mash is typically composed of various grains, such as barley, corn, rye, and wheat, which undergo fermentation. During the distillation process, the sugars present in these grains are converted into alcohol by yeast. This process is fundamental to creating the unique flavor profiles and characteristics of whiskey, as different grains impart different tastes and qualities to the final product.

Fruits, herbs, spices, or sugarcane, while important in the production of other types of spirits (like rum or flavored liqueurs), do not play a role in whiskey production, further emphasizing the importance of fermented grain mash in this context.