Beer

Although beer is more complicated to produce, it was developed earlier in history than wine at around 6000 b.c. By definition beer is an alcoholic drink derived from grains. The most common source of beer is barley, with rice and corn used as adjuncts. The per capita consumption in Europe is about 32 gal of beer a year, whereas in the United States the per capita consumption is about 25 gal. Beer is made by malting barley to obtain a- and /^-amylases, then by mashing, which is a process in which more grain (adjuncts) and water are added to the malt. The mixture is heated slowly to first achieve proteolysis (35°C for 1 h) and then starch hydrolysis (67-68°C for 20-30 min); finally, the enzymes are inactivated (mashing off at 75-80°C). The main purpose is to allow a- and ^-amylase to degrade am-ylose and amylopectin to yield glucose and maltose for fermentation by yeast, because yeast cannot degrade starch directly. The liquid (which can be considered as nutrient broth for yeast) is separated from the husks of the grains by lautering and sparging. Basically these are filtration and rinsing steps to obtain clear liquid for fermentation. The resultant clear fluid is called wort. Before addition of yeast for fermentation, the wort is boiled and hops (Hu-mulus lupulus) is added to give the bitter flavor of beer. After cooling to 8.8°C, yeast is added (pitching). Saccha-romyces carlsbergensis (bottom yeast) is the yeast of choice for lager beer making. Fermentation continues for three to four days, at which time a lot of foam is developed in the fermentation vessel (Krausen formation). After five days, the Krausen collapses and after 10 to 12 days fermentation ceases. At this stage the beer is called green beer. Yeast cells can be recovered for animal feed, and C02 is collected and later injected into finished beer for foam formation. The green beer is aged for about three months before being bottled for sale. Beer can be sold in unpasteurized form (draft beer), which has a short shelf life. Most of the beer on the market is pasteurized at 57.2 to 60°C for 15 to 20 min in bottles and cans. Some beers are filtered and not pasteurized (draft canned beer). Beer made in the preceding manner is called lager beer, and the alcohol content is about 3.5 to 4%. Using S. cerevisiae (top yeast), ale can be made that has about 6% alcohol. European beers are "heavier" because they use only barley, which has more protein than barley used in the procedure in the United States, where barley is mixed with rice and corn adjuncts that decrease the total protein contents.

Light Beer. Light beer is made by using enzymes such as glucoamylase and pullulanase along with the a- and fi-amylases to convert all the starch to fermentable sugar; thus, no sugar is left in the beer after fermentation. The beer has fewer (lighter) calories than the regular beer, which has residual starch. Light beer still has calories from alcohol since 1 g of alcohol provides 7 cal of energy.

Dry Beer. Dry beer was started in Japan. Japanese beer has a sweeter taste than Western beer and is not blended.

By a process called superattenuated fermentation, special yeast strains are used for prolonged fermentation, resulting in the utilization of all the sugars. In dry beer making, no enzyme is added to reduce the carbohydrate.

Ice Beer. This is the newest entry into the beer market. Beer is first made and then quickly frozen to obtain small ice crystals. The beer is then filtered through a membrane that retains the ice crystals. The reason behind this process is that the ice crystal will capture undesirable compounds of the beer with a resultant smoother beer. Some people think that this is just another commercial effort to keep consumers entertained by having another style of beer. Because the water is removed from the beer during the freezing and filtration processes, ice beer has a higher alcohol content of about 6% compared with regular beer.

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