Sorghum beer brewing using Eleusine coracana “finger millet” to improve the saccharification

Abstract

Three Eleusine coracana “finger millet” varieties (Musama, N161 and Mwamba) from Rwanda were studied with a view to improve the saccharification during the mashing of red sorghum malt (Kigufi, variety of Rwanda). Traditional mashing procedure (infusion) and decantation mashing procedure were employed and the produced worts were assessed for their brewing qualities. The findings prove that β-amylase activities of Musama (301.6 U mL - 1), N161 (227.2 U mL - 1) and Mwamba (112.6 U mL) malts were much higher than in Kigufi sorghum malt (73.3 U mL - 1). The mashing of the mixture of sorghum malt with Rwandan finger millet (Musama variety) malt allowed to produce more fermentable sugars, particularly maltose, reaching amounts 2-fold higher than when pure sorghum malt was used. Moreover, when the decantation method is applied, the fermentable sugars content draws a 100% increase by comparison to the traditional mashing method (infusion). However, the free amino nitrogen the worts obtained by decantation mashing procedure was slightly lower than that of the worts obtained by traditional mashing procedure, but was still within the range needed for yeast growth. In African context, Eleusine coracana malt could be used for improve the conversion of sorghum starch into fermentable sugars during sorghum beer brewing.