A German law, the title of which signifies pledge of purity or order of purity, governing the production and quality of beer in Germany. William VI, the Elector of Bavaria, decreed in 1516 that only water, malted barley, malted wheat, and hops could be used to make beer. Yeast was not included but taken for granted. This law is still in effect today in Germany. The malt acquires a brilliant external appearance while the endosperm becomes black.
Roasted malt is used to flavor and color stout and dark beers.
The second, slower stage of fermentation, carried out in closed vessels at 44 - 48 Fahrenheit for 22 days. Used to calculate the amount of extract in wort or beer. Primary fermentation occurs at 59 - 77 Fahrenheit and lasts for about one week. A variety of barley in which only the central spikelet is fertile, forming two rows of grains each. It is the variety most appreciated for brewing because its kernels are better developed and the husk is thinner.