Ethanol can be manufactured from a variety of feedstock or raw materials. While the feedstock used to produce renewable ethanol typically varies depending on market conditions, the majority of ethanol biorefineries are built to specifically process either grains or sugar beets. Currently in Europe, ethanol is mostly produced from renewable feedstock, such as corn, wheat, barley and sugar beet. The sugars contained in these feedstock are converted into ethanol through fermentation.
There are several steps in the production process of ethanol, of which the most important are:
The ethanol production process can vary depending on the feedstock used. However, the end product is always the same: a clear colourless liquid.
The production process for ethanol made from cellulosic material, waste or residues is a more complex process that requires breaking down the feedstock into fermentable sugars. The feedstock for this kind of ethanol is typically from the non-edible parts of crops such as straw, corn cobs and husks, and also dedicated energy crops. For the future, the biodegradable fraction of municipal solid waste is considered to be a promising feedstock.
The production of cellulosic ethanol requires innovative technology in the form of enzymatic hydrolysis and pre-treatment. Once the sugars are extracted from the feedstock, they follow the same process as ethanol from food and feed crops.