Grain 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-fermentable sugars 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.

A typical primary mash ingredient is grain that has been malted. Modern-day malt recipes generally consist of a large percentage of a light malt and, optionally, smaller percentages of more flavorful or highly colored types of malt. The former is called "base malt"; the latter is known as "specialty malts".

The grain bill of a beer or whisky may vary widely in the number and proportion of ingredients. For example, in beer-making, a simple pale ale might contain a single malted grain, while a complex porter may contain a dozen or more ingredients. In whisky production, Bourbon uses a mash made primarily from maize (often mixed with rye or wheat and a small amount of malted barley), and Single Malt Scotch exclusively uses malted barley.

Each particular ingredient has its own flavor that contributes to the final character of the beverage. In addition, different ingredients carry other characteristics, not directly relating to the flavor, which may dictate some of the choices made in brewing: nitrogen content, diastatic power, color, modification, and conversion.

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