What Part of the Corn Plant is Used to Make Ethanol?

Identification

• Ethanol refiners add enzymes to ground corn to form "slurry," to which they add yeast. The mixture ferments and is then distilled to remove an alcohol called ethanol. Most refineries, according to the U.S. Department of Energy, use "dry milling" to prepare corn for refining. Hammer mills grind corn into a fine powder.

Types

• Only the starches and sugars from corn's seed, or kernels, are used to make corn ethanol. After they ferment in water and enzymes, the liquor is distilled to produce ethanol. Cellulosic ethanol draws from an entire plant, which may be corn, sugar cane or other local crop. The majority of American ethanol is corn ethanol, which uses only the corn kernels.

Considerations

• Waste grain fiber is processed for use in animal feed and fertilizers; refiners also recover and bottle carbon dioxide expelled during fermentation. Liquid called "stillage" is separated from corn during refinement and from waste solids during drying and recycled to slurry tanks.