Isolation and characterization of shochu yeasts with superior brewing ability from shochu mashes

Abstract

Seven yeasts with superior ability in terms of alcohol fermentation and aromatic ingredient generation were isolated from 272 wild yeasts obtained from shochu mashes of shochu breweries. These seven yeasts were examined for their fermentation ability with rice and sweet potato using small scale of fermentation tests. Moreover, their thermotolerance was evaluated by growth tests and fermentation tests with barley koji. Among the isolated seven yeasts, the shochu yeast "MF062" was superior in the characteristics of fast fermentation, high alcohol production, aromatic ingredient generation and thermotolerance. It was named the "Heisei Miyazaki Yeast". From the results of analyses of physiological and genetic characteristics of MF062, it was shown to be a Saccharomyces cerevisiae, but it showed different characteristics from the industrial yeasts used in shochu production. Using a sweet potato shochu brewing test, with 60 kg of raw materials and yeast MF062, it was confirmed that a high alcohol production yield and a high quality shochu could be obtained. © 2011 The Institute of Brewing & Distilling.