SCREENING YEAST STRAINS FOR THEIR ABILITY TO PRODUCE PHENOLIC OFF-FLAVOURS: A SIMPLE METHOD FOR DETERMINING PHENOLS IN WORT AND BEER

Abstract

Amounts of several phenolic compounds in wort and beer were measured by gas-chromatography following extraction with a small volume of chloroform. The procedure described is not specific for phenols and the limit of sensitivity is 0·05–0·1 μg ‘phenol’/ml. However, the precision is reasonable and this relatively rapid method has proved useful for screening yeast strains for their ability to produce phenolic off-flavours. Phenolic-tasting beers contained significant amounts of 4-vinyl guaiacol; whilst this compound may not be the sole cause of the undesirable flavour, its production is symptomatic of the unsuitability of a yeast strain for brewing.