Production Process of Ethanol: Fermentation

Learn about the process of ethanol fermentation at Burt Process Equipment. We carry heavy duty Grundfos pumps, designed to meet the needs of biofuel production.

With concerns about global energy supplies, and the desire to develop sustainable sources, the efficient production of biofuels is more important than ever. Biodiesel production, ethanol production and research into other alternative fuels requires commitment as well as the best processes and most robust equipment. Today’s bioethanol fermentation begins with either the dry milling or wet milling of corn or other grains, which is then fermented to create ethanol. During the fermentation process, microbes are used to convert glucose into ethanol. Learn about the production process of ethanol and discover why it’s so important to use top quality, robust pumps.

Preparing Corn for Fermentation – Dry Milling Versus Wet Milling 

These two initial processes differ in terms of how the raw grain is treated, as well as the products that are created. In the U.S., approximately 80 percent of bioethanol production uses dry milling. 

 With dry milling, the whole kernel is ground into meal and water is added for form “mash.” Enzymes are then added, converting the starch into sugar. The substance is cooked before being transferred to the fermenters, at which point yeast is added and the sugar to alcohol conversion begins. After the fermentation process is complete, the “beer” is separated from the “stillage,” and the ethanol is distilled and dehydrated. A denaturant is added to make the ethanol undrinkable. 

 In the wet milling process, the grain is separated into its components by soaking. After it is sufficiently steeped, the resulting slurry is sent through grinders, which separates out the corn germ. Remaining gluten, fiber and starch is further separated. The gluten (protein) is filtered and dried for animal feed, while the rest of the starch is fermented into ethanol, in a similar way as the dry milling process.