going to say a. The two types of fermentation that most people are familiar with are ethanol fermentation and lactic acid fermentation. Ethanol fermentation is the process by which yeast and some types of bacteria convert sugar into alcohol and carbon dioxide. This process is used for making bread and producing alcoholic beverages such as beer, wine and hard cider. One common nonalcoholic beverage that is . produced via the fermentation process is tea. After the green leaves of the Camellia sinensis plant are steamed and dried, they are fermented, modifying the flavor. This is how oolong and black teas are made. In many beverage fermentation processes, the carbon dioxide not used in carbonation is released into the atmosphere. During the process of bread making, the ethanol alcohol from the fermentation evaporates. One can find physical evidence of fermentation during this process by smelling the characteristically yeasty aroma of rising dough.One type of lactic acid fermentation is used to culture yogurt from milk. During this type of fermentation, lactose is turned into lactic acid, which is the substance that produces the slightly sour taste in yogurt. Lactic acid fermentation is a somewhat simpler process than ethanol fermentation, and produces mostly lactic acid with little gas byproduct. Incidentally, lactic acid fermentation also occurs in the muscles of animals when more quick energy is needed than the flow of oxygen can supply. It is the source of some non-injury muscle soreness.Though often used in controlled environments, these two types of fermentation can also occur accidentally or as a result of neglect, which generally results in ruined products like sour milk or rotten fruit. Although fermentation is a helpful culinary technique that helps to preserve certain foods, the process is best done intentionally. It is essential that most foods are refrigerated at the proper temperature in order to maintain freshness.
