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Yeast, German

This yeast in many distilleries forms an important by-product of the manufactory, and is collected and sold under the name of dry yeast for the use of the private brewer and baker. When this is done, the process adopted is nearly as follows. Crushed rye is mashed with the proper quantity of barley and malt, and the wort, when made, cooled to the proper temperature. For every hundred pounds of the crushed grain there are now added half a pound of carbonate of soda and six ounces of oil of vitriol (sulphuric acid) diluted with much water, and the wort is then brought into fermentation by the addition of yeast. From the strongly fermenting liquid the yeast is skimmed off and strained through a hair sieve into cold water, through which it is allowed to settle. It is afterwards washed with one or two waters, and finally pressed in cloth bags till it has the consistency of dough. It has a pleasant, fruity smell, and in a cool place may be kept for two or three weeks. It then passes into a putrefying decomposition, acquires the odour of decaying cheese, and has the property of changing sugar into lactic acid instead of into alcohol as before. A hundred pounds of crushed grain will yield six to eight pounds of the pressed yeast. It is made largely at Rotterdam, and is imported thence to this country through Hull. German yeast is excellent when it can be procured fresh, but this is rather a difficulty. After being purchased it should be taken out of the paper as soon as possible, and laid in a cool place till wanted. An ounce of German yeast will raise a quartern or half a gallon, or three pounds and a half of flour.