[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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In traditional process of making Scotch malt whisky, two types of yeast are used simultaneously. The one is distiller's yeast and another is brewer's yeast. Effects of using brewer's yeast were investigated from the viewpoint of flavor components in fermented mash. The amounts of ethyl esters of fatty acid (ethyl caproate, ethyl caprylate, ethyl caprate and ethyl laurate) were larger in the mash fermented with distiller's and brewer's yeasts than that with distiller's yeast alone. This phenomenon was remarkable when the amount of linoleic acid in wort was increased. It was suggested that this effect was related to the difference in the ability to incorporate linoleic acid between distiller's and brewer's yests. The use of brewer's yeast accelerated the growth of lactic acid bacteria in the fermented mash. As a result, characteristic sweet flavor was produced in the fermented mash. In whisky fermentation, brewer's yeast tended to die more rapidly than distiller's yeast at high temperature. It was considered that the growth of lactic acid bacteria was influenced by this phenomenon.

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Four indices for phenolic compounds proposed by Glories were used to classify Japanese red wines and to compare Japanese wines with foreign wines. Figty-five samples of Japanese red table wines, 11 “nouvesu” type and 44 ordinary wines, as well as 5 samples of high-grade chateaux in Bordeaux, 1982 were analyzed. The Japanese ordinary wines showed higher HC1 index (% of acid depositive polymerized tannin), lower EtOH index (% of 90% EtOH depositive tannin binding with polysaccharides), lower gelatin index (% of gelatin coagulable tannin) and lower polymerized pigment index (% of non decolorized pigment by SO₂) than the Bordeaux wines.
From principal component (PC) analysis of the 4 indices and 9 analytical values (concentrations of tannin and anthocyan, A₂₅₀, A₄₂₀, A₅₃₀, A₅₃₀/A₄₂₀, L*, a*, b*) of the Japanese wines, two price classes of the Japanese ordinary wines and the Japanese “nouveau” type were clearly distinguished. PC analysis of the 4 indices of the Japanese and Bordeaux wines showed that the 1st PC was smoothness and astringency while the 2nd PC was youthfulness of color and tannin. The Bordeaux wines and the Japanese “nouveau” type wines were plotted at 1st and 2nd quadrant, respectively. Majority of the Japanese ordinary wines was plotted at 3 td and 4 th quadrant, and severalexpensive ones were plotted at 1st quadrant.

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It was recognized that strongly bitter wines had a tendency to contain large amounts of isoamyl alcohol and small amounts of n-propyl alcohol in the white wines fermented by various yeast strains. Therefore, the bitter taste of these higher alcohols were studied by sensory tests using model wines. Strong bitter taste was pointed out on wine with low concentration of isoamyl alcohol (200 mg/l). In addition, wines containing more than 111 mg/l of n-propyl alcohol showed significant increase of body, but they also showed unpleasant taste because of excess n-propyl alcohol.

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