A metabolic effect is produced on yeast by hops. The modifier, not yet specifically identified, is a component of the whole lupulin glands of hops. To the brewer, the side reactions and excretory products of the alcoholic fermentation by yeast—the higher alcohols, esters, aldehydes, and organic acids—are basic to the taste properties of beer. The involvement of a metabolic modifier from hop extractives then becomes suspect to having an effect on the results of these side reactions in fermentation.
Keywords: hop extracts, GTC stability, fermentometer, yeast