Starch Hydrolysis During Sorghum Beer Brewing

Samples were taken at different stages of sorghum beer brewing and the starch isolated. The physico‐chemical properties of the starch were determined to establish what changes occurred at the molecular level of the starch during brewing. Complete hydrolysis of the starch to fermentable sugars is never the aim of mashing during sorghum beer brewing. A certain amount of starch in the beer is required to give it its characteristic viscosity and body. This residual starch was found to be much reduced in amylose content as well as in molecular size compared with the starch in the raw materials. Debranching with isoamylase followed by gel filtration chromatography indicated that the amylopectin side chains were reduced in length by approximately half.