Effects of processing methods on sorghum wort filtration

Abstract

Effects of processing methods on sorghum wort filtration were investigated using three mashing processes to produce wort namely; infusion at 65°C, modified mash at 80°C and modified mash at 100°C. Sorghum was malted at the temperatures of 20°C and 25°C for 8 days to produce two types of malts. Well-modified barley malt was used as control. Brewing parameters measured were filtration rate, specific gravity, viscosity, reducing sugars, hot water extract, soluble extract level, fermentable extract level, and fermentability level. Results revealed that though the sorghum worts had faster filtration rate than barley in infusion at 65°C, other brewing parameters were all inferior to those of barley malt. In both modified mash at 80°C and modified mash at 100°C barley wort had higher filtration rate than the two sorghum malts. Sorghum malted at 20°C had better filtration in 80°C mashing process while sorghum malted at 25°C performed better in modified mash at 100°C. The other brewing parameters obtained from the two sorghum malts in these two modified mashing methods were comparable to those of barley malts and were adequate for brewing purposes. The results in this work showed that the performances of the two sorghum malts improved in terms of filtration; indicating that well-modified sorghum malts with appropriate processing method could eliminate filtration problems associated with sorghum brewing. The effects of malt quality and processing methods on the sorghum wort filtration rate and other brewing parameters were significant at p<0.05. Sorghum malts could therefore be processed without filter aids.

Keywords: sorghum malt, wort, processing, extract yield, filtration

Nigerian Food Journal Vol. 23 2005: 218-224