Optimization of Mashing Conditions When Mashing with Unmalted Sorghum and Commercial Enzymes

Small-scale mashing experiments were carried out with 100% unmalted sorghum grist. A commercial mashing program with temperature stands at 50, 95, and 60°C was carried out. A heat-stable α-amylase, a bacterial protease, and a fungal α-amylase were used in all experiments. The effects of the addition of various commercial enzymes, the adjustment of the calcium level of the mash-in liquor, and the adjustment of the initial pH of the mash were observed. An optimum mashing procedure suitable for the production of wort from unmalted sorghum was developed. The optimization results suggested that the potential for brewing a high-quality beer from unmalted sorghum could be improved by 1) adjusting the mash-in liquor to give a calcium content of 200 parts per million; 2) adjusting the mash-in pH to 6.5; 3) using a mashing program with temperature-time stands of 50°C x 50 rain, 80°C x 10 min, 95°C x 40 min, and 60°C x 30 min; 4) using a heat-stable α-amylase (120 U/g of grist, added at the end of the 50°C stand), a neutral protease (100 U/g of grist, added at mash-in), and a fungal α-amylase (600 U/g of grist, added at the start of the 60°C stand); and 5) adjusting the pH to 5.5 prior to the 60°C stand.