yeast

(yest or yest) [A. S. gyst.] ferment consisting of a culture of Saccharomyces cerevisias or other species of S. The yeast fungus is a blastomycete some species of which are pathogenic; see blastomycosis, Saccharomyces Torula. cul'tivated y., one of the forms of yeast propagated by culture and used in bread-making, brewing, fermentation, etc. wild y., any of the uncultivated forms of yeasts, usele as ferments and sometimes pathogenic.