english version for beer.docx

1、english version for beerThe Brewers HandbookBy Ted GoldammerPublisher：Apex PublishersDecember 2000Barley Malts(selected excerpts)Barley malt is to beer as grapes are to wine. It is ideally suited to brewing for many reasons. Malted barley has a high complement of enzymes for converting its starch su

2、pply into simple sugars and contains protein, which is needed for yeast nutrition. Of course, one important element is its flavor. There are two types of barley: six-row and two-row.Barley MaltsMaltingMalting serves the purpose of converting insoluble starch to soluble starch, reducing complex prote

3、ins, generating nutrients for yeast development, and the development of enzymes. The three main steps of the malting process are steeping, germination, and kilning.Barley SteepingSteeping begins by mixing the barley kernels with water to raise the moisture level and activate the metabolic processes

4、of the dormant kernel. The water is drained, and the moist grains are turned several times during steeping to increase oxygen uptake by the respiring barley. Generally, the barley spends about 40 hours in tanks of fresh, clean water, with three intervals during which the water is allowed to drain. D

5、raining is done to remove dissolved carbon dioxide and to reintroduce oxygen-rich water. Steeping is complete when the white tips of the rootlets emerge, which is known as chitting. At this point the grains will have swollen one and one-third times their original size.Barley GerminationIn the next s

6、tep, the wet barley is germinated by maintaining it at a suitable temperature and humidity level until adequate modification has been achieved. Germination is done on floors, in drums, or in boxes. Floor malting is an old process in which the chitted malt is spread on the floor to a height of 10 to

7、20 cm. Germination in drums is still done, but is not very economical; consequently, only a few plants still use this system.Malt KilningThe final step is to dry the green malt in the kiln. Malts are kilned at different temperatures. The temperature regime in the kiln determines the color of the mal

8、t and the amount of enzymes which survive for use in the mashing process. Low temperature kilning is more appropriate for malts when it is essential to preserve enzymatic (diastatic) power. These malts are high in extract but low in coloring and flavoring compounds. Pilsner and pale ale malts are ex

9、amples of malts kilned at low temperatures. Malts kilned at intermediate temperatures, such as Munich and Vienna malts, are lower in enzymes but higher in coloring and flavoring compounds. Malts kilned at high temperatures, such as crystal and chocolate malts, have little if any enzymes, thus are lo

10、wer in extract.Barley MaltsMalt Constituents Malt is largely made up of carbohydrates, which are composed of insoluble cellulose, soluble hemicellulose, dextrins, starch, and sugars. Cellulose constituents do not contribute to fermentable extract or desirable flavors in the malt. Hemicellulose is a

11、constituent of the endosperm cell walls, which consist largely of beta-glucan. Dextrins are residual, unfermentable fractions of amylopectin. Starch, accounting for about 60 to 65% of the malts weight, is composed of amylose, which is reduced to maltose and maltotriose and amylopectins that decompos

12、e into glucose. Glucose, a monosaccharide, accounts for about 1 to 2% of the total starch found in a barley kernel. Maltose, a disaccharide or double-sugar, is most closely associated with brewing and is formed by two molecules of glucose. Another disaccharide present in malt is sucrose. The only si

13、gnificant trisaccharide or triple-molecule sugar in brewing is maltotriose. Maltotriose is slowly fermentable by most strains of brewing yeast.Barley MaltsMalt Extracts Malt extracts can be used as a sole source of fermentable sugar, or they can be combined with barley malt. The malt extract comes i

14、n the form of syrup or dried powder. If the final product is a dried powder, the malt extract has undergone a complete evaporation process by means of spray-drying, thus removing almost all of the water. For simplicity, use an 85% conversion factor when substituting dried malt for syrup. Syrups are

15、more popular than dried malt extract, possibly because they are less trouble to store. A common problem noticed in malt extract beers is the thin, dry palate, which correlates with a low terminal gravity. Another common problem is the lack of a true dark malt flavor in dark beers.Hops(selected excer

16、pts)Hops, a minor ingredient in beer, are used for their bittering, flavoring, and aroma-enhancing powers. Hops also have pronounced bacteriostatic activity that inhibits the growth of Gram-positive bacteria in the finished beer and, when in high enough concentrations, aids in precipitation of proteins.HopsHop Constituents Hops contain hundreds of components, but of particular interest are resins, oils, and polyphenols.Hop Resin