THE VISCOSITY OF WORTS IN RELATION TO THEIR CONTENT OF β‐GLUCAN

Abstract

A procedure is given for assessing that proportion of wort viscosity which is attributable to β‐glucan. Worts obtained from unkilned samples of malt which have been processed for 54 or 72 h show enhanced viscosity. This is principally due to β‐glucan although the contribution of other constituents, absent from the wort of fully modified malt, is of significance. Barley variety is shown to have a pronounced effect on wort viscosity. Insoluble β‐glucan is brought into solution in mashes at 65° C. The β‐glucan isolated from malt which has been inactivated using aqueous ethanol prior to extraction at 65° C, is of higher specific viscosity than that isolated from control worts prepared at the same temperature. The introduction of a rest by mashing initially at 40° C results in the production of wort of lower viscosity, a decrease in the β‐glucan content of the wort and a reduction in the specific viscosity of the β‐glucan. There is no apparent relationship between the endo‐β‐glucanase content of the malts and either the viscosity of derived worts or the degree of breakdown of β‐glucan which occurred during malting and mashing. Abrasion of barley, which is a factor assisting the distribution of enzymes during malting, acts to reduce wort viscosity. 1972 The Institute of Brewing & Distilling