Improved Production of a Spanish-Type Sherry by Using Selected Indigenous Film-Forming Yeasts as Starters

Abstract

In a series of experiments aimed at improving production of an unfortified Spanish-type sherry (Vernaccia di Oristano), the yeast flora were identified in various samples of must and flor. Thirty yeast strains isolated from the flor were subjected to functional selection, and the most suitable were used as starters in winery aging trials. The functional selection showed that Saccharomyces prostoserdovii and Sacch. bayanus (the species most frequently found in the flor) were almost equally strong fermenters, but Sacch. prostoserdovii was superior in the maturation phase. The aging trials showed that Sacch. prostoserdovii used alone produced a wine of the highest quality with more reliable and more uniform aging in one third of the time normally taken.