Ethanol Production Process

Below is a simplified pictorial of the basic ethanol production process.


The entire corn kernel is first ground into a fine meal.  The meal is slurried with water to form a mash. Enzymes are added to the mash to convert the starch to dextrose, a simple sugar. Ammonia is added for pH control and as a nutrient to the yeast.

The mash is processed in a high-temperature cooker to reduce bacteria levels ahead of fermentation. The mash is cooled and transferred to fermenters where yeast is added and the conversion of sugar to ethanol and carbon dioxide (CO2) begins.

The fermentation process generally takes about 40 to 50 hours. During this part of the process, the mash is agitated and kept cool to facilitate the activity of the yeast. After fermentation, the resulting “beer” is transferred to distillation columns where the ethanol is separated from the remaining stillage. The ethanol is concentrated to 190-proof using conventional distillation and then is dehydrated to approximately 200-proof in a molecular sieve system.

The stillage is sent through a centrifuge that separates the coarse grain from the solubles. The solubles are then concentrated to about 30% solids by evaporation, resulting in Condensed Distillers Solubles (CDS) or syrup. The coarse grain and the syrup are then dried together to produce dried distillers grains with solubles (DDGS), a high quality and nutritious livestock feed.

Contact us for a tour of Didion Ethanol and our team would be happy to give you further details of our innovative ethanol production process.