As corn-based fuel ethanol production has risen over the past decade, there has been interest in the volume of distillers" grains produced. Distillers" grains are a byproduct from dry-mill ethanol plants and can be used in livestock rations, particularly by ruminants such as beef and dairy cattle. Since most of the expansion in fuel ethanol production has been in corn-based dry mill plants, production of distillers" grains has shown a rapid expansion as well.
Figure 7 provides an indicator of the growing importance of distillers" grains by showing estimates of the amount of corn utilization that produces distillers" grains from dry mill fuel ethanol production. Calculations are based on data provided in Hoffman and Baker, Market Issues and Prospects for U.S. Distillers" Grains Supply, Use, and Price Relationships, USDA-ERS Outlook Report No. FDS-10K-01, December 2010.
To arrive at the estimates for corn that produces distillers" grains from dry mill fuel ethanol production, two steps are made in the calculations. First, the volume of corn used in dry mill fuel ethanol (and by-products) production is separated from the volume used for all ethanol (and by-products) production. This share has risen from 30-35 percent a decade ago to about 90 percent in 2010/11. Second, since about 17.5 pounds of distillers" grains are typically produced from each bushel of corn used in dry mill ethanol production, 31.25 percent (17.5 lbs. distillers" grains per each 56 pound corn bushel) of the corn used in dry mill ethanol production was allocated to the production of distillers" grains. Based on these assumptions, the amount of corn that produces distillers" grains from dry mill fuel ethanol plants is expected to account for about 11 percent of total corn utilization in 2010/11.
Allocation of corn to the production of other ethanol byproducts, such as corn gluten feed and corn gluten meal from wet-mill ethanol plants, are not separated in this depiction. For more information regarding the breakout of these categories, see the Hoffman and Baker report cited above.