DIACETYL PROBLEMS IN BREWING AND THEIR CONTROL

Abstract

Brewer’s yeast, Saccharomyces cerevisiae,  and some bacteria of  Lactobacillus  group (common contaminents of  beer) are responsible for diacetyl (DA) production in beer, which results in  ‘cheesy’ or  salty off-flavour. While consumers dislike beer containing more than 0.07 ppm of DA,  usually  alcoholic beverages far exceed this limit (0.3 to 50 mg/1), making it necessary for brewers to  exerise  control over DA production in beer. The traditional methods of DA control in beer, lagering of beer and addition of fresh yeast cells to fermented beer, are tedious in operation and suffer from  inefficiency and economy. The newly proposed methods, immobilized yeast cells technique and diacetyl  reductase technique, though expensive in their present form, are highly efficient and absolutely  reliable.