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

The solubility of beta-glucan was monitored in barley during malting, as were the effects of mashing conditions on the levels of beta-glucan in wort and beer derived from well and poorly modified malts. Significantly higher soluble beta-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 beta-glucan solubility increased for up to 3 days of germination but decreased in the later stages of germination. The proportion of soluble beta-glucan was significantly increased when extraction temperature was increased from ambient to 45 degrees 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 degrees C, there was an increase in the amount of beta-glucan solubilized in wort and that survived into the resulting beer. The beta-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.