The dry grind ethanol production method is a rigorous
biological process that requires stringent quality control.
For example, bacterial contamination at mashing may
result in the formation of acids that divert glucose from
ethanol production and interfere with fermentation. Moldy
grain, improper grain storage, faulty equipment, reintroduced
stillage, and air are some of the major sources
of contamination that can reduce ethanol yields or impact
the value of the distillers grains.