Variations in Solubility of Barley β-Glucan during Malting and Impact on Levels of β-Glucan in Wort and Beer

Abstract

The solubility of β-glucan was monitored in barley during malting, as were the effects of mashing conditions on the levels of β-glucan in wort and beer derived from well and poorly modified malts. Significantly higher soluble β-glucan proportions were observed in green malts after germination for 4 and 5 days. However, if the endogenous malt enzymes were inactivated by heat treatment, then β-glucan solubility increased for up to 3 days of germination but decreased in the later stages of germination. The proportion of soluble β-glucan was significantly increased when extraction temperature was increased from ambient to 45°C. Well and poorly modified malts were mashed at different mashing temperatures, and as the temperature was raised over the range of 45 to 75°C, there was an increase in the amount of β-glucan solubilized in wort and that survived into the resulting beer. The β-glucan contents of wort and beer from poorly modified malt were very high at all temperatures, emphasizing the importance of avoiding the presence of undermodified malt in a grist; even at lower mashing temperatures, the endogenous enzymes are incapable of fully solubilizing problematic glucans that have not been removed during malting.