Study of two wine strains rehydrated with different activators in sluggish fermentation conditions

Abstract

Rehydration of active dry yeasts is essential in wine fermentation. To help yeast cells withstand the extreme conditions during alcoholic fermentation, adjuvants are added to the must. However, few commercial activators are added directly to the yeast rehydration water, even though this might render hydration more efficient due to a favorable osmotic gradient. The effect of five “metabolic activators” added directly to the water to rehydrate two commercial wine yeast strains in sluggish fermentation conditions was evaluated; these conditions were achieved by acid and osmotic stress. Cell vitality, sugar consumption, glycerol, ethanol and nitrogen contents at 8 and 15 days of process were determined. Furthermore, discrepancy in glucose and fructose consumption was also measured. Ergosterol at certain doses generally showed a favorable effect, so that it could be considered a good activator compared with other molecules involved in essential metabolic cycles.