MICRO-SCALE MALTING AND BREWING STUDIES OF SOME SORGHUM VARIETIES

The malting and brewing characteristics of three sorghum varieties were investigated in a micromalting and microbrewing plant. The optimum malting conditions for Sorghum vulgare c.v. Fara Fara (Australia), Sorghum bicolor (South Africa) and Sorghum vulgare c.v. SK5912 (Nigeria) were found to consist of steeping for 21 h, at 30°C, initial germination at 30°C for 24 h, followed by a further germination period of 4 days at 25°C. Kilning temperatures of 50°C and 82°C were investigated. Evidence of the presence of hydrocyanic acid was found. The extent of modification in all malts was markedly irregular with the kernels showing brown coloration on the outer layers. The brewing trials with 100% sorghum malt showed a slow and incomplete saccharification, slow lauter tun filtrations and very difficult beer filtrations. By supplementing commercial enzymes in the mash only the speed of lauter tun filtration improved significantly.