YEAST

n. Yest. Gr., UJKIJ. Lat., fermentum. Fr., levure. Ger., Hefe. A semi-fluid, viscid, flocculent scum forming on the surface of a saccharine juice when it is in a state of vinous fermentation. Y. is composed chiefly of Saccharomyces. Ordinary y. is beer y. [a, 35.] Beer y. Lat., fermentum [U. S. Ph., 1870], cerevisice fermentum [Br. Ph.]. Fr., levure (de biere). Ger., Bierhefe. The ferment (see SACCHAROMYCES cerevisioB) obtained in brewing beer. It is insoluble in water or alcohol, has a dirty-yellowish color, a bitter taste, and a sourish odor. Its ultimate composition, according to Schlo berger, is carbon 49'9 per cent., hydrogen 6'6 per cent., nitrogen 12'1 per cent., and oxygen 31'4 per cent. If separated from its nitrogenous principle, it becomes inert as a ferment. It has been used as an external stimulating poultice, and internally in typhoid and similar fevers, and against succe ive eruptions of boils, [a, 35.J Bottom y. The y. that settles when fermentation is restrained by cold, [a, 35.] German y. Ger., Pre hefe, Pfundhefe. Y., such as that produced for baking purposes, containing a minimum amount of alcohol. The fluid in which the y. forms is drained away and the y. mixed with dry starch. It is free from the bitterne of hops, [a, 35.] Top-y. The y. formed on the surface of fermenting liquids, [a, 35.] Y. cakes. Cakes made by pre ing and drying y. that has been put into sacks and washed with water, [a, 35.] Y. plant. The genus Saccharomyces, especially the Saccharomyces cerevisice. [a, 35.] Y. poultice. See Cataplasm a FERMENT I. [s. 739]