The process of converting starch to ethanol is called "fermentation".
Fermentation is a biological process that converts sugars, such as glucose, into ethanol and carbon dioxide. In the case of starch, it must first be hydrolyzed (broken down) into simpler sugars, like glucose, before it can be fermented. This hydrolysis is usually achieved through the addition of enzymes, such as amylases. Once the starch has been converted into simpler sugars, yeast or bacteria are added to initiate the fermentation process, in which the sugars are converted into ethanol and carbon dioxide. This process is widely used in the production of alcoholic beverages, such as beer and wine, as well as in the production of biofuels, such as ethanol.