How is Ethanol Made?

Ethanol is most commonly found as a fuel additive.  Using ethanol is supposed to decrease dependence on oil, and it is debatable whether or not it achieves this goal.  I am not going to address this issue, as I will just state the facts.   Most gas stations use a mixture of about 10% ethanol with the rest normal gasoline.  The added ethanol has many advantages.  Compared to gasoline, ethanol burns much cleaner, as it contains more oxygen than gas, which has more carbon.  As a result, when burned ethanol releases oxygen instead of carbon dioxide to the environment.  Because of its high oxygen content, pure ethanol fuel has a very high octane rating.  This means that it will have a higher performance in your cars engine.  For this very reason, the Indy Racing League only uses 100% ethanol is all of their race cars.  Ethanol also has a very low freezing point, so it acts as a anti-freeze in the gas lines of your cars engine.  This also will allow your car to start easily at low temperatures.

Now that we know some reasons that ethanol is used, lets take a look at how it is made.  To make ethanol, a lot of corn is needed.  Corn is about 70% starch, 6% germ, 14% water, and 10% fiber.  To expose the starch for processing, the kernels are dumped into a grinder and ground into corn "flour".  Liquid is then added to the flour to create a mash.  This mash is heated in order to further break down the starch into sugar.  After cooling, the new mash is transported to a fermentation tank.  Yeast is added to begin the fermentation process where the sugar is made into alcohol.  After fermentation is complete, the alcohol has to be purified by removing the solid mash and water.  This process is called distillation, this process is repeated until the alcohol is 95% pure.  This almost pure alcohol goes through a molecular sleeve where the bigger alcohol molecules are separated from the water molecules.  When finished, the final product is 200 proof, or 100% alcohol.  This is shipped to a refinery for other processes to allow it to be added to gasoline.  The leftover syrup is added to the leftover mash and dehydrated to be sold to farms for use as cattle feed.  This mash, now called distiller grains has a nutritional value equal to or even better than whole corn.