A scotch mash bill is a document that outlines the specific grains and proportions used to create a particular scotch whisky. It is similar to a recipe, and it can vary significantly from distillery to distillery. The mash bill is an important factor in determining the final flavor and character of a scotch whisky.
The most common grains used in scotch whisky are malted barley, unmalted barley, and corn. Malted barley is barley that has been soaked in water and then allowed to germinate. This process releases enzymes that convert the starches in the barley into sugars. Unmalted barley is barley that has not been malted. It is used to add body and sweetness to the whisky. Corn is used to add sweetness and smoothness to the whisky.