加利啤
Malt
Malt is germinated cereal grains that have been dried in a process known as "malting". The grains are made to germinate by soaking in water, and are then halted from germinating further by drying with hot air. Malting grains develops theenzymes required to modify the grain's starches into sugars, including the monosaccharide glucose, the disaccharidemaltose, the trisaccharide maltotriose, and higher sugars called maltodextrines. It also develops other enzymes, such asproteases, which break down the proteins in the grain into forms that can be used by yeast. Malt also contains small amounts of other sugars, such as sucrose and fructose, which are not products of starch modification but were already in the grain.
Malted grain is used to make beer, whisky, malted shakes, malt vinegar, confections such as Maltesers and Whoppers, flavored drinks such as Horlicks, Ovaltine and Milo, and some baked goods, such as malt loaf, bagels and rich tea biscuits. Malted grain that has been ground into a coarse meal is known as "sweet meal". Various cereals are malted, thoughbarley is the most common. A high-protein form of malted barley is often a label-listed ingredient in blended flours typically used in the manufacture of yeast breads and other baked goods.
Hops
Hops are the female flowers (also called seed cones or strobiles) of the hop plant, Humulus lupulus. They are used primarily as a flavoring and stability agent in beer, to which they impart a bitter, tangy flavor, though hops are also used for various purposes in other beverages and herbal medicine.
In the Middle Ages, beers tended to be of a very low alcohol content (small beer) and were commonly consumed as a safer alternative to untreated water. Each village tended to have one or more small breweries with a barley field and a hop garden in close vicinity.[citation needed] Early documents include mention of a hop garden in the will of Charlemagne's father, Pepin III. However, the first documented use of hops in beer as a flavoring agent is from the 11th century.[citation needed] Before this period, brewers used a wide variety of bitter herbs and flowers, including dandelion, burdock root, marigold, horehound(the German name for horehound means "mountain hops"), ground ivy, and heather.
Hops are used extensively in brewing for their antibacterial effect that favors the activity of brewer's yeast over less desirablemicroorganisms and for many purported benefits, including balancing the sweetness of the malt with bitterness, contributing a variety of desirable flavors and aromas.[citation needed] Historically, traditional herb combinations for beers were believed to have been abandoned when beers made with hops were noticed to be less prone to spoilage.
Yeast
Brewing yeasts may be classed as "top-cropping" (or "top-fermenting") and "bottom-cropping" (or "bottom-fermenting").[44]Top-cropping yeasts are so called because they form a foam at the top of the wort during fermentation. An example of a top-cropping yeast is Saccharomyces cerevisiae, sometimes called an "ale yeast". Bottom-cropping yeasts are typically used to produce lager-type beers, though they can also produce ale-type beers. These yeasts ferment well at low temperatures. An example of bottom-cropping yeast is Saccharomyces pastorianus, formerly known as S. carlsbergensis.
Decades ago, taxonomists reclassified S. carlsbergensis (uvarum) as a member of S. cerevisiae, noting that the only distinct difference between the two is metabolic. Lager strains of S. cerevisiae secrete an enzyme called melibiase, allowing them to hydrolyse melibiose, a disaccharide, into more fermentable monosaccharides. Top- and bottom-cropping and cold- and warm-fermenting distinctions are largely generalizations used by laypersons to communicate to the general public.
The most common top-cropping brewer's yeast, S. cerevisiae, is the same species as the common baking yeast. Brewer's yeast is also very rich in essential minerals and the B vitamins (except B12). However, baking and brewing yeasts typically belong to different strains, cultivated to favour different characteristics: baking yeast strains are more aggressive, to carbonate dough in the shortest amount of time possible; brewing yeast strains act slower, but tend to produce fewer off-flavours and tolerate higher alcohol concentrations (with some strains, up to 22%).