Control of Glucanolysis in Mashing. S. Home, K. Pietilä, and K. Sjöholm, VTT Biotechnical Laboratory, Tietotie 2, P.O. Box 202, SF-02151 Espoo, Finland. J. Am. Soc. Brew. Chem. 51:0108, 1993.

Malt always contains small amounts of β-glucans, which may cause problems either in lautering or in beer filtration. The effects of mashing variables on the solubilization and hydrolysis of β-glucans were studied both on a laboratory and an industrial scale. Well- and poorly modified malts produced from the two-row barley varieties Kustaa and Kymppi were used. In addition, the use of unmalted barley as an adjunct was studied. The optimum mashing-in temperature for glucanolysis was 48° C. Starch gelatinization and other heat-induced structural changes in the coarse grist particles seemed to contribute to the solubilization of β-glucans at high temperatures. By extension of the mashing-in period, the majority of the β-glucans from unmalted barley could be hydrolyzed by the malt β-glucanases. Trials on an industrial scale showed that the mash tun design and the efficiency of stirring and heating have a marked effect on the release and hydrolysis of β-glucans. The effects of the mashing variables on the β-glucan concentrations in final wort were minor when well-modified malt was used.

Keywords: β-Glucan, β-Glucanases, Grist coarseness, Mashing, Mash thickness, Stirring