Brewing and fermentation are two of the most common methods of producing alcoholic beverages. Brewing is the process used to create beer, while distillation produces spirits, such as whiskey, gin and vodka. Fermentation, the biological process in which plant sugars are consumed and ethanol is produced, is an important part of both processes.
Fermentation is a biological processes in which sugars, such as glucose and fructose, are converted into energy. It produces carbon dioxide and ethanol as waste products. To produce fermentation, brewers or distillers seal a plant product in an airtight environment and add yeast. The yeast breaks down the plant sugars, releasing several waste products. For the purposes of making alcoholic beverages, the most important of these waste products is ethanol, also known as ethyl alcohol or pure alcohol.
Brewing is one method of using fermentation to produce an alcoholic beverage. In brewing, a brewer processes germinated grain, typically barley, by drying, milling and steeping in water and heating. This produces a cereal mash to which the brewer adds hops and sometimes, other ingredients. The brewer adds yeast to the resulting mixture and allows it to ferment before removing it from the fermentation tank for further processing. Once the liquid produced by this process has aged, it can be filtered and is ready to be served as beer.
Distillation is the process of separating different liquids by heating. In the case of alcoholic beverages, the initial steps of the process are similar to brewing. The distiller allows grain to germinate, then steeps it in water, dries it, roasts it, grinds it and mixes it with water before adding yeast to the resulting mixture to ferment it. The distiller then heats this mixture, allowing the resulting vapor to condense. The condensed vapor will be high in alcohol content. The distilling process can be repeated several times. After distilling, the product requires further processing and aging before being drinkable.
Other Uses of Fermentation
In addition to brewing and distilling, fermentation is used to produce other forms of alcoholic beverages. Vinting is the process of creating fruit-based alcoholic beverages, such as wine and cider. Fermentation is also part of the process of making bread. Bakers add yeast to dough and allow it to ferment. The heat of baking evaporates the ethanol produced by fermentation, but it is the carbon dioxide emitted as a waste product which creates bubbles within the dough, causing bread to rise.
References and ResourcesYoBrew; Alcoholic Fermentation by Yeast Cells
British Beer and Pub Association; The Brewing Process
Loch Lomond Distillery; Making Scotch Whisky