Storage of pitching yeast for production of whisky

Abstract

The viability of pitching yeast stored at 5°C and at 20°C was compared. The viability of the yeast stored at 5°C was about 80% after 54 d storage and its CO2 producing activity also remained high. The ethanol production rate of yeast stored for a long period at 5°C was unaffected in a subsequent fermentation test, even though the viability was only about 50%. The ethanol production rate of yeast stored at 20°C decreased in proportion to a rapid decrease in viability during storage. The concentration of intracellular sulphur compounds, important for the production of aromatic components of whisky, of yeast stored at 5°C was higher than that of yeast stored at 20°C. Therefore, the storage of yeast at 5°C seems appropriate for production both of ethanol and aroma.