The Fermentability of Worts Produced from Some Sorghum Varieties and their Combinations with Malted Barley using Saccharomyces uvarum

This study was carried out to investigate the fermentability of worts produced from some sorghum varieties and their combinations with malted barley using Saccharomyces uvarum. The infusion method of mashing was used with the addition of external enzymes (amylase, protease and glucanase) for the sorghum wort production. The yeast (Saccharomyces uvarum) was pitched in worts from three varieties (CSR-01, CSR-02 and Samsorgh-17) of sorghum (Sorghum bicolor), barley and their combinations. Changes in some process parameters like pH, apparent extract, free alpha amino nitrogen (FAN), yeast concentration and yeast viability were investigated over a period of six-day fermentation. Results showed that the pH value of the samples reduced from 5.6 to 4.6, the apparent extract of the samples reduced from 12.50 to 3.00oP, free alpha alpha amino nitrogen (FAN) value of the samples also reduced drastically from 150.00 to 34.00 mg/l in the course of the fermentation process from the first day to the six day. However, there were increases in some other parameters checked during the fermentation process. Total acidity increased from 5.6 to 4.6 on the pH scale, yeast viability evaluation showed a slight increase from 96 to 99 % and the yeast concentration also increased from 216 x 104 to 280 x 104 cells/ml. The apparent fermentability of the samples which is an experiment that gave the overall information on the rate at which the fermenting yeast cells were able to assimilate the available nutrients in the wort and consequently convert the available fermentable sugars into alcohol and carbon dioxide showed that barley malt, CSR-01 malt, CSR-02 malt, 50 % barley & 50 % CSR-01, 50 % barley & 50 % CSR-02, 50 % barley & 50 % samsorgh-17, 25 % barley & 75 % CSR-01, 25 % barley & 75 % CSR-02, 25 % barley & 75 % samsorgh-17 wort samples had apparent fermentability of 72.00, 37.50, 44.00, 36.00, 50.00, 62.00, 48.00, 42.00, 53.00, and 42.00 % respectively. 50 % barley & 50 % CSR-02 wort sample had the highest apparent fermentabilty (62 %) compared with other samples used in the study in relation to barley (72 %). 50 % barley & 50 % CSR-02 wort sample had better brewing qualities than CSR-01 and Samsorgh-17 with their combinations, as the yeast ( Saccharomyces uvarum) proliferates well in its wort during the fermentation process.