beer, alcoholic beverage made by brewing and fermenting cereals, especially malted barley, usually with the addition of hops as a flavoring agent and stabilizer. One of the oldest of alcoholic beverages (there is archaeological evidence dating to c.3000 B.C.), beer was well known in ancient Egypt, where it may have been made from bread. At first brewed chiefly in the household and monastery, it became in late medieval times a commercial product and is now made by large-scale manufacture in almost every industrialized country, especially Great Britain, Germany, the Czech Republic, and the United States.
Although British, European, and American beers can differ markedly in flavor and content, brewing processes are similar. A mash, prepared from crushed malt (usually barley), water, and, often, cereal adjuncts such as rice and corn, is heated and rotated in the mash tun to dissolve the solids and permit the malt enzymes to convert the starch into sugar. The solution, called wort, is drained into a copper vessel, where it is boiled with the hops (which provide beer with its bitter flavor), then run off for cooling and settling. After cooling, it is transferred to fermenting vessels where yeast is added, converting the sugar into alcohol. Modern beers, typically lighter than ancient, contain about 3% to 6% alcohol.
Beers fall into two broad categories. Ales are made with yeast that ferments more quickly at warmer temperatures and tends to rise to the surface. Lagers use yeast that ferments more slowly at cooler temperatures and tends to settle, and they are aged at cold temperatures for weeks or months, hence the name [Ger., Lager = storage place]. Most major American beers are lagers; many are Bohemian Pilsners, a golden-hued lager. Bock beer, said to take its name from Einbeck, Prussia, where it was first made, is a heavier, usually darker lager. Pale ale is generally a light to dark amber, strongly hopped beer. Porter is a strong, dark ale brewed with the addition of roasted malt to give flavor and color. Stout, an ale which is darker and maltier than porter, has a more pronounced hop aroma and may attain an alcoholic content of 6% to 7%. Light, or low-calorie, beer is lower in alcohol content. Ice beer is a higher-alcohol beer produced by chilling below 32°F (0°C) and filtering out the ice crystals that form.
In the 1980s, consumer dissatisfaction with the taste and choice offered by major breweries led to the growth of more traditional "craft" breweries and microbreweries—firms that produce fewer than 15,000 barrels annually—especially in the United States. By 2010 there were in the United States several dozen regional craft breweries, more than 600 microbreweries, and more than 1,000 brewpubs (a microbrewery that sells mainly through its own restaurant or bar).
See G. Oliver, ed., The Oxford Companion to Beer (2011).