What is a Mash Bill?
Mash ingredients, mash bill, or grain bill are those materials used in brewing from which a wort can be obtained for fermenting into alcohol. Mashing is the act of creating and extracting fermentable and non-fermentablesugars and flavor components from grain by steeping it in hot water, and then allowing it to rest at specific temperature ranges in order to activate naturally-occurring enzymes in the grain that convert the starches to sugars. The sugars will be separated from the mash ingredients and then converted to alcohol and other fermentation products by yeast in the brewing process.
Basically, it’s the ingredients used to make bourbon. The only other things you need are yeast, a still and a barrel. A bourbons mash bill has to be at least 51% corn. Typical mash bills include corn, rye and barley. Occasionally, the rye is replaced with wheat or other grains to change the flavor of the bourbon. The majority of mash bills used today are 70/20/10 corn/rye/barley +/- a little bit based on the distillery.