THE EFFECT OF OSMOTIC PRESSURE ON THE INTRACELLULAR ACCUMULATION OF ETHANOL INSACCHAROMYCES CEREVISIAEDURING FERMENTATION IN WORT

An intracellular accumulation of ethanol was observed in Saccharomyces cerevisiae during the early stages of fermentation (3 h) in wort. However, after 12 h fermentation, the intracellular and extracellular ethanol concentrations were similar. Increasing the osmotic pressure in wort by adjusting the carbohydrate concentration, from 10° to 20° plato, was observed to cause an increase in intracellular ethanol concentration and glycerol production. Although intracellular ethanol concentration increased, no adverse effect was observed on cell growth and fermentation rates. Thus, increasing the carbohydrate concentration in wort to at least 20° plato did not affect cell growth and fermentation rates, but did result in the production of more ethanol.