Overview

Ethanol is a high octane, liquid, domestic and renewable fuel, produced by the fermentation of plant sugars. In the United States, ethanol is typically produced from corn and other grain products, although in the future it may be economically produced from other biomass resources such as agricultural and forestry wastes or specially grown energy crops.

Extracting ethanol from grain is a fermentation / distillation type process, similar to that used to produce beverage alcohol. To produce ethanol from grain, the starch portion of the grain is exposed and mixed with water to form a mash. The mash is heated and enzymes are added to separate the fermentable sugars. The next phase, fermentation, involves the addition of yeast to convert the sugars to ethanol and carbon dioxide. Fermentation produces a mixture called "beer," which contains about 10 percent ethanol and 90 percent water. The "beer" is then boiled in a distillation column to separate the water, resulting in fuel-grade ethanol that is 85 to 95 percent pure. Ethanol production from grain utilizes only the starch. A variety of highly valued feed co-products, including gluten meal, gluten feed and dried distillers grains, are produced from the remaining protein, minerals, vitamins and fiber and are sold as high-value feed for livestock.