Formation of Aroma Components during “Secondary Fermentation” by the yeast

Studies on The Brewing of Alcoholic Beverage by the system of Fermentation Following after Saccharification (Part 8)

Abstract

The formation of aroma components during “secondary fermentation” was studied by the addition of yeast having a high activity of i-amyl acetate formation to sake.
Isoamyl acetate, & -phenylethyl acetate and esters of fatty acids were formed during “secondary fermentation”. On the other hand the change of i-amyl alcohol was minimal, so the ratio of i-amyl acetate to i-amyl alcohol increased.
Isoamyl alcohol was necessary to form i-amyl acetate by the yeast during “secondary fermentation”. Isoamyl acetate was formed in spite of existence of i-amyl acetate of up to 10 ppm in the sake
The use of immobilized yeast was effective for i-amyl acetate formation during “secondary fermentation”.
The quality and flavor of the sake were improved by “secondary fermentation”.