Ethanol comes from plants, and in the U.S., it is primarily made from excess field corn that would otherwise go to waste. The ethanol production process uses only the starch from the corn kernel to create fuel; the leftovers, called distillers grains, are then used for animal feed.
To create ethanol, producers use a distilling process that uses enzymes and microorganisms to extract the starch from corn. It is then converted to 200-proof alcohol, which is ethanol. The carbon dioxide, proteins, nutrients and other compounds that are left over are sold to other organizations for animal feed or use in beverage carbonation.