The art of brewing is of great antiquity. Inscriptions of Egyptian life show that beer was a popular beverage on the banks of the Nile around 3000 B.C. Beer is made throughout the world from starchy materials such as rice, maize, millet, and wheat, but the basic material is generally barley, with hops providing extra flavouring and preservative properties. The specially grown and selected type of barley is first converted into malt, by being steeped in water and allowed to germinate under carefully controlled conditions of temperature and humidity. The malt is then dried and cured according to the type of beer required. Next, the malt is crushed and mixed with hot water for the mashing process. The water used in this process plays a considerable part in determining the character of the beer. These days, the water is artificially treated with minerals, but originally breweries were set up near sources of suitable water (e.g., Burton-on-Trent in England and Pilsen in the Czech Republic).
During the mashing process the enzymes produced in malting convert the insoluble starch to soluble sugars which, together with other soluble substances from the malt, constitute the solution called 'wort'. The wort is now run into coppers and the hops are added. Only the dried green cones of the female hops, rich in resins and oils, are used. The wort and hops are boiled, and then filtered and cooled, and yeast is added to promote fermentation. After fermentation the beer is cooled, stored for a period dependent upon the brewery and type of beer, filtered, pasteurized (in most cases), and run off into barrels, bottles, or cans for despatch.
Brewing of Beer
Commercial beers are made by a process that is basically the same throughout the civilized world. The malt is ground to a coarse grist, is weighed, and is placed in a mash tub, or mash tun, where water and a mash of other cereals are mixed in. The prepared cereal mash usually is cooked to liquefy the starch and then is added to the malt fraction. The malt's enzymes convert the starch into fermentable sugars- maltose and dextrin. The resultant liquid, called wort, is filtered through a mash filter, or lauter tub. It then flows into the brewing kettle where hops are added, and the mixture is boiled for several hours. After the brewing operation the hop wort is filtered through a hop separator, or hop jack. The filtered liquid is pumped through a wort cooler and flows into a fermenting vat where pure-culture yeast is added for fermentation.
In making beer, 7 to 11 days are required for the conversion of all the fermentable sugars into alcohol and carbonic acid gas (CO2). Beer uses a "bottom-fermentation" yeast strain, and the temperature of the mass is kept between 38° and 48° F (3.3°-9° C). For ale a "top-fermentation" yeast strain is used, and the temperature varies from 50° to 70° F (10°-21°C). Five to six days is sufficient time to complete an ale fermentation. In all cases the carbonic acid gas produced by fermentation is collected, compressed, and stored, to be returned later to the beer.
The freshly brewed beer, to which a small portion of unfermented wort is added to ferment slowly at a low temperature, is then stored in tanks; that is, lagered (from the German word lagern, "to store"). The beer is kept at a temperature of 33°-34° F (0.5°-1.1° C) for several months to permit mellowing and sedimentation. When it is ready for packaging, it is filtered under pressure at the low lager temperature. The precise amount of carbonic acid gas desired is returned to the brew, and the beer is packaged in bottles, cans, or barrels.
Barreled, or draft, beer, intended for quick consumption, is marketed without further processing. Most bottled or canned beer, intended for shelf storage up to four months (cans) or six months (bottles), is pasteurized to prevent further fermentation.
United States beers vary in alcoholic content from 3.6 percent to 4.9 percent by weight, while the special beer marketed as "malt liquor" varies from 4.08 percent to 6.3 percent by weight. Ales average about 4.2 percent by weight.
The caloric values of beers and ales vary in accordance with the alcohol, protein, and carbohydrate content of the individual brand. The average United States beer has some 12% to 13% calories per ounce. Bock beer, malt liquor, ale, stout, and porter are fuller bodied and have higher caloric values.
Storing and Serving Beer
Since beer is affected by light, bottled beer should be stored in a dark place and, like canned beer, should be kept cool. Beer should be served at a temperature of about 45°F (7°C) and ale at 50°F (10°C). Beer glasses should be cleaned and rinsed carefully. Soap or soapy water should not be used. Any soapy film on the inside of the glass will break down the "head," or collar of foam, on top of the beer. Beer should be poured straight into the glass. Tilting the glass so the beer pours down the side reduces the collar on the beer.