mash bill is a term used in the United States whisky industry to describe the combination of Poaceae grains (most notably corn, rye, barley, and wheat) that represent formulas for straight whisky recipes, especially in bourbon and rye whiskies. An accounting term from the mid-twentieth century, “mash bill” originally denoted the prices of different grains in costing out the formulation of whisky recipes for mashing and fermentation. Mixed grain recipes were the convention in colonial American whisky since the beginning of American distilling in the early seventeenth century, although there are notable exceptions. See whisky, rye.
Mash bills—when combined with yeast strains, varying fermentation times and conditions, and different types of distillation plant and practices, as well as the bourbon custom of adjusting acidity by the sour mash method—all affect the flavor of the distillate. Grain is the primary component in the base cost of manufacturing whisky, but as commodities the various grains used can vary in price by season; in the past, this led to some fluctuations in mash bills, which of course influenced the flavor of the finished whisky.
Nonetheless, beginning in 1938 the United States regulated the minimum grain-volume thresholds for labeling of straight whiskies: 51 percent corn for bourbon whisky, 80 percent corn for corn whisky, 51 percent rye or rye malt for rye whiskies, 51 percent wheat for wheat whisky, and 51 percent malted barley for malt whisky. This meant that a distillery’s cost of production could vary more from year to year, but it gave the consumer a more consistent, trustworthy product.
Today, each distillery usually has a house or proprietary mash bill for their whisky, and often more than one if they make several brands.
In making mixed-grain spirits, American distillers were of course following a practice that was centuries old in continental Europe and the British Isles. On the Continent, the Dutch made their genever from Baltic and local rye mashed with malted barley for saccharification. See genever. Similarly, Scandinavian, German, and Russian distillers were grain captives to their cold-climate rye and barley, although sometimes wheat was used as well, and in some cases, particularly in Germany, malted rye replaced the barley malt. See aquavit; korn; and vodka. Government regulations also impacted grain proportions for mash recipes, particularly in Britain, where a progressively punitive malt tax was enacted in 1697, reached a zenith in 1770, and was only abolished in 1880. This forced distillers to economize by increasingly using unmalted grains to mitigate the duty. By the late eighteenth century, Irish whisky was commonly one-third each green barley, malted barley, and oats or rye. Scotland had similar mash recipes, with local bere (an ancient barley landrace) and black oats the predominant grains. By the mid-nineteenth century, continuous patent stills were in wide use, substituting local cereals with cheap imported maize and wheat, subject to commodity prices. See whisky, grain; whisky, Irish; and whisky, scotch. For the Asian approach to mixed-grain spirits, see baijiu.
Beresford, John. Observations on … the State of the Distilling Trade in Ireland. Dublin: 1782.
Craig, H. Charles. The Scotch Whisky Industry Record. Dumbarton, UK: Index, 1994.
Federal Alcohol Administration Act. 96 Article II of Regulations 5. Washington DC, March 1, 1938.
Hall, Harrison. The Distiller, 2nd ed. Philadelphia: 1818.
Royal Commission on Whiskey and Other Potable Spirits. Interim report. London: HM Stationery Office, 1908, sections 1768–1941; 14232–14320.
By: Chris Middleton