Ethanol Process

View the Flow Chart
  • Grain Receiving



    WPE can store up to 1.8M bushels of grain. All grain is received by truck, and is then stored until it is processed.
  • Mash Preparation


    Grain is milled into a flour and then mixed with water and enzymes. The enzymes help to break down the starch that is present in the grain into sugar molecules.
  • Fermentation


    During the fermentation process, yeast metabolize sugar molecules into ethanol and carbon dioxide. This process typically takes 60 hours to complete, and results in a liquid product that we call beer that contains about 14 w/v% alcohol.

    190 Proof

    The beer from the fermentation step is pumped to the distillation system where the ethanol is stripped away from the water and non-starch components of the grain. The ethanol stream leaving distillation is 190 proof, which is 95% pure ethanol.
  • Molecular Sieves

    200 Proof

    To further concentrate the ethanol up 200 proof (99.5%+ ethanol), we use molecular sieves which trap water molecules and allow pure ethanol molecules to pass through.
  • Storage


    WPE has 2 large storage tanks to store product in until it is shipped out by truck or by rail.
  • Fuel Ethanol

    Fuel-grade ethanol is 200 proof ethanol that has been denatured with approximately 2.5% gasoline. This product is sold to fuel blenders to be blended down to E10 (i.e. 10% ethanol, 90% gasoline) or E15 (i.e. 15% ethanol, 85% gasoline) before it is shipped to gas stations.
  • Centrifugation



    The water and non-fermentable (i.e. oil, protein, fiber) portions of the grain are separated by large centrifuges.

    Wet Distiller's Grains (also called WDG, WDGS, and Wet Cake) is a high-protein, high-energy animal feed product. The product from WPE is predominately fed to beef and dairy cow operations within our geographical region.
  • FEED

    The production from WPE is pre-dominantly fed to beef and dairy cow operations within our geographical region. See the distiller's section on this webpage for more detailed nutritional information.
  • Evaporation

    Process Condensate


    Evaporation is used to further concentrate the liquid stream from the centrifugation process. The resulting product is called syrup and is around 32%-34% solids.


    A distillers dryer is used to convert the wet distiller's grains (65-67% moisture) to dry distiller's grains (10%-12% moisture).

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Grain Receiving

Grain is delivered by truck to the ethanol plant where it’s loaded in storage bins designed to hold enough grain to supply the plant for 7-10 days.

Grain Pricing and Information


Distiller's Information