Optimization of microbiological fermentation parameters for Vinsanto wine production

Vinsanto is a dessert wine produced in Italy, mainly in Tuscany, from non-aromatic grapes. Its production follows a traditional basic scheme, with main differences arising from must characteristics (grape varieties and grape drying) and from fermentation and aging conditions, all these leading to the different Vinsanto styles (Domizio and Lencioni, 2011). The organoleptic characteristics of Vinsanto change year by year, because of the very poor control of the traditional process, especially regarding the management of the fermenting yeast population. Moreover, must inoculations with commercial yeast strains, carried out over recent years by some vineries, for the most part led to extremely dry Vinsanto, with zero or very low residual sugar. With the aim to manage the fermentation process to obtain Vinsanto wines with valuable and reproducible characteristics, we tested different fermentation conditions: three yeasts strains in pure culture or co-inoculum (S. cerevisiae, C. zemplinina and Z. florentinus), two sugar concentration (24% and 35% w/v) and three fermentation temperature (10°C, 14°C and 20°C ). The fermentation behavior of pure and mixed culture as well as the analytical profiles of final products were evaluated.