2001 AACC Annual Meeting Charlotte, North Carolina October 14-18, 2001 Charlotte Convention Center

The effects on wort quality when mashing with unmalted sorghum (0-100%) and malted barley (100-0%) together with industrial enzymes were evaluated. Mashing was carried out using a program with stands at 50 C, 95 C, and 60 C. Mashes were supplemented with combinations of different industrial enzymes (Hitempase (H), Bioferm (B) and Bioprotease (P)). Hitempase was found to be essential for efficient saccharification. The inclusion of Bioferm in mashes with a high sorghum content gave filtration rates that were comparable to 100% malted barley mashes. Bioprotease gave increases in the amount of proteolysis. As the percentage sorghum in the grist was increased, corresponding decreases in filtration, colour, viscosity, attenuation limit, free amino nitrogen, high molecular weight nitrogen, and a corresponding increase in pH were observed. The soluble nitrogen index decreased from 46 (20% sorghum H+B+P) to 10 (100% sorghum H+B+P), indicating that as the percentage sorghum was increased, less of the available proteinaceous material in the mash was solubilised. Worts containing high proportions of sorghum had a lower total amino acid content than malted barley worts. With the addition of just 20% malted barley, there were significant increases in the soluble nitrogen index, the apparent attenuation limit, the high molecular weight nitrogen fraction and the free amino nitrogen fraction when compared to a 100% unmalted sorghum wort. Therefore, the addition of malted barley to unmalted sorghum mashes could improve the potential for brewing a high quality lager beer from unmalted sorghum.