Influence of Some Process Parameters on Defined Characteristics of Sorghum Beer during Very High Gravity Fermentation

Abstract

This study was carried out to investigate the influence of some process parameters on defined characteristics of sorghum beer during very high gravity fermentation. The yeast (Saccharomyces uvarum)was pitched in very High Gravity Wort from two varieties (red and white) of sorghum (Sorghum bicolor). Changes in some process parameters like pH, specific gravity, percentage alcohol by volume, free amino nitrogen, total reducing sugar, total nitrogen and total protein were investigated over a period of 5 days of fermentation. Results showed that pH values decreased as fermentation proceeded with increased total acidity while alcohol contents of the fermenting wort increased from the first day to the fifth day of fermentation. There were observed decrease in specific gravity, total reducing sugar, free amino nitrogen (FAN), Percentage total nitrogen and Percentage total protein from first day to the fifth day of fermentation. The red sorghum had a lower pH, higher specific gravity and alcohol content than the white sorghum. This showed that Saccharomyces uvarum can grow well in very high gravity sorghum wort and pH, specific gravity, free alpha amino nitrogen is an important aspect of the wort for yeast fermentation.