Ethanol

Ethanol is produced using the following process:
1. Wheat or corn kernels are ground in a hammermill to expose the starch.
2. The ground grain is mixed with water, cooked briefly and enzymes are added to convert the starch to sugar using a chemical reaction called hydrolysis.
3. Yeast is added to ferment the sugars to ethanol.
4. The ethanol is separated from the mixture by distillation and the water is removed from the mixture using dehydration.
A new process is under development for making ethanol from the cellulose and hemicellulose components of cheaper biomass feedstocks such as wood and agricultural residues. The method is similar to the traditional process that uses the starch component of grain or corn. However, this method is more difficult because these types of feedstock require more complex pretreatment and hydrolysis steps that use acid or enzymes before the sugars can be fermented to ethanol.