Brewing is the process used to make such alcoholic malt beverages as lager beer and ale. The chief ingredients used in brewing are barley malt and other cereal grains, as well as hops, yeast, and water. In the part of the brewing process called fermentation, the yeast converts the sugar obtained from the grains into alcohol. Most beers contain from 2 to 6 percent alcohol.
All brewers use the same basic brewing process. This article describes the basic process, which consists of six major steps: (1) malting, (2) mashing, (3) boiling, (4) fermentation, (5) aging, and (6) finishing.
Malting
produces certain chemical and physical changes in barley, the chief grain used in making most beers. Barley malt contains starch and protein, as well as enzymes that are essential to the brewing process. Malt provides much of the flavor in beer.
To produce barley malt, brewers soak the barley in water from one to several days to increase its moisture content to the desired level. The barley is then placed in special chambers where it is allowed to germinate (sprout) for several days. Next, the barley is moved to large ovens called kilns, where it is dried and the germination process is halted. Brewers start the drying process at a low temperature and gradually increase the heat to 180 °F (82 °C). They then remove the sprouts and store the grain, now called malt, for a minimum of 4 weeks.
Mashing.
Brewers grind the barley malt and mix it with water to form a mash. They also make a mash of other cereal grains, such as corn and rice. The mashes are combined and heated to about 155 °F (68 °C). During the heating process, enzymes in the malt liquefy the grain and convert the starch to sugar and other, more complex carbohydrates (substances composed of carbon, hydrogen, and oxygen). The mixture is filtered to remove grain kernels. The remaining amber liquid, called wort, is transferred to large kettles for boiling.
Boiling.
During the boiling process, dried blossoms of the hop plant are added to the wort. The hops prevent spoilage and add aroma and flavor to the brew. After boiling, brewers clarify and cool the wort.
Fermentation.
To promote fermentation, brewers add yeast to the wort. Yeast converts the sugar in the wort into alcohol and carbon dioxide. Brewers remove the carbon dioxide and store it for various uses in the brewery. Fermentation takes about a week. After fermentation, most of the yeast is removed from the brew.
Aging
improves the taste of beer. Brewers age beer in storage tanks for several weeks or months. Some brewers age beer by fermenting it a second time.
Finishing.
After the beer has been aged, brewers further clarify and filter it several times to remove the remaining yeast. The beer is then packaged in bottles, cans, or stainless steel kegs. Most bottled or canned beer is pasteurized before being packaged.
History.
Brewing was developed more than 6,000 years ago. Several ancient peoples, including the Babylonians and Inca, brewed beer. Large-scale commercial brewing began in Germany in the A.D. 1100’s. A brewery established in 1632 in New Amsterdam (now New York City) was probably the first brewery in North America. Today, the United States produces about 6 billion gallons (23 billion liters) of alcoholic malt beverages annually.
See also Alcoholic beverage; Beer; Fermentation; Hop; Malt.
