Relationships Among the β-Glucan Contents of Barley, Malt, Malt Congress Extract, and Beer

Abstract

Malting barley breeders have directed a sustained effort toward reducing β-glucan problems through selection of lines exhibiting low barley β-glucan content. The impetus for this effort has arisen because of brewing problems associated with increased amounts of β-glucan in wort and beer. The relationship between the β-glucan content of a barley and that of its finished beer, however, has not been clearly examined. This study determined β-glucan contents in barley, malt, and Congress extract in an effort to define this relationship and to determine which best predicts levels obtained in beer. The impact of environment and genotype on this relationship and prediction was also considered. In total, 60 samples of barley and the corresponding malts, Congress fine-ground extracts, and beers were analyzed for β-glucan content using the Calcofluor-flow injection method of analysis. It was shown that β-glucan contents of malt and Congress extract were highly correlated with levels detected in the beer produced from those malts. The correlation between the β-glucan content of barley and beer was significantly lower. This study also demonstrated the strong influence of environmental growing conditions on the β-glucan contents of barley, malt, Congress extract, and beer, although the genetic component was also significant for malt, Congress extract, and beer.