How is Fuel Ethanol Produced?
The production of ethanol from corn can be accomplished by one of two separate production methods: wet mill or dry grind. In both cases, corn starch is broken down into sugar for conversion to ethanol. In the wet mill process, the starch is separated prior to conversion. In the dry grind process, the starch is processed with no separation. Today, all new plant construction uses dry grind technology. In the dry grind process, the entire corn kernel is first ground into corn flour. The corn flour is diluted with water, and enzymes and steam are utilized to break the corn starch into sugar. As the sugar is liberated, yeast converts the sugar to ethanol and carbon dioxide. After fermentation is complete, the resulting slurry is distilled to separate the ethanol from the remaining corn mash and stillage. Remaining traces of water are removed from the ethanol and the resulting fuel alcohol is then blended with a denaturant, such as natural gasoline, to render it undrinkable and thus not subj
