FERMENTATION OF WORTS MADE FROM 100-PERCENT RAW SORGHUM AND ENZYMES

Worts made from raw sorghum and enzymes were successfully fermented ev en though the level of FAN present (51 mg/1) is well below that essent ial for fermentation of wort made from malted barley. Changes in typic al fermentation parameters such as specific gravity, pH uptake of free amino nitrogen (FAN) and ammonium ions mirrored the increase in yeast cell concentration. Yeast viability remained high throughout the ferm entation. Under identical fermentation conditions, malted barley worts showed typical fermentation profiles. However, malted barley worts wi th specific gravity maintained by the addition of D-glucose, but in wh ich the FAN was diluted to a level similar to that found in a wort mad e from sorghum and enzymes, fermented more slowly and failed to attenu ate fully. Five consecutive fermentations, using yeast cropped from th e preceding to pitch the current fermentation were conducted. The spec ific gravity profiles were essentially the same in all five fermentati ons. Final values of pH, yeast in suspension, yeast viability and FAN were also indistinguishable. The yeast crop taken from fermentations o f worts made from raw sorghum and enzymes represented a 5-fold increas e over the initial pitching rate. When compared to commercial beers, t he beers derived from fermentation of worts made from raw sorghum and enzymes contained lower levels of ethyl acetate, and higher levels of both 2- and 3-methyl butanol. In the beers derived from sorghum, isobu tanol was always less than 20% of the total higher alcohol concentrati on.