The effect of temperature on the production of aromatic compounds using Heisei Miyazaki yeast MF062 was compared between 10 industrial yeasts. All yeasts tested produced characteristic patterns of alcohols and esters in fermentation tests with rice‐koji at 20, 28 and 38°C. The concentration and composition in mature moromi with rice‐koji at 20, 28 and 38°C were almost the same as those with barley‐koji. Therefore, it was suggested that fermentation temperature is an important factor in the production of aromatic compounds. MF062 produced almost the same concentration of β‐phenethyl alcohol at both 38 and 28°C. The concentration was higher than that generated by the other 10 yeasts. MF062 produced higher concentrations of i‐butyl alcohol than the other yeasts at higher fermentation temperatures. Moreover, compared with the other yeasts, MF062 produced a lower concentration of acetate, which can give an off‐flavour in excess concentrations in shochu. The production of acetoin was divided into two groups – a high producing group and a low producing group – at all temperatures. MF062 belonged to the latter group and showed preferred characteristics in the production of shochu, resulting in a high concentration of preferred aromatic compounds and a low concentration of compounds that impart an off‐flavour. Copyright © 2013 The Institute of Brewing & Distilling

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.

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