Effects of Using Brewer's Yeast on the Flavor Components of Whisky Fermented Mash

Abstract

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.