Spontaneous and inoculated yeast populations dynamics and their effect on organoleptic characters of Vinsanto wine under different process conditions.

ABSTRACT

Evolution of the microbial composition during the production of Vinsanto wine was investigated under different fermentation conditions to determine their impact on the yeast population and the wine sensorial characteristics. Fermentations were carried out according to the traditional process in 50-l barrels. Different fermentation conditions were applied (yeast inoculum, "mother sediment" addition and temperature) to standardise the Vinsanto production process. Fermentations and products were monitored over the aging period by chemical, microbial and sensory evaluation. The low temperature at the beginning of the fermentations under traditional cellar conditions results in prolonged survival of the non-Saccharomyces yeast. In contrast, Saccharomyces yeast populations dominated throughout the fermentation when the temperature of the cellar was maintained at a constant 16-18 degrees C. Results indicate that inoculation with a commercial yeast strain and fermentation temperature strongly influence the evolution of Vinsanto wine. The "mother sediment" seems to have no direct role as a microbiological starter in Vinsanto production but, despite this, it does have a strong influence on the sensory attributes of the Vinsanto wine. Our work highlights the importance of managing the fermenting microflora to improve the sensorial characteristics of Vinsanto wine.