Taxonomic singularities of the veil of Flor yeasts in Fino Wines from the D.O. Jerez-Xérèz-Sherry

Abstract

The veil of “Flor yeasts” are responsible for the biological aging process of wines produced in the D.O. of Jerez and Sanlúcar de Barrameda (Finos and Manzanillas) in the province of Cádiz and Fino in the D.O. Montilla-Moriles in the province of Córdoba, as well as in other wine-growing regions of the world, such as France, South Africa, California, Sardinia or Hungary. The first attempts to classify these flor veil yeasts were based on biochemical assays of sugar assimilation and fermentation. Thus, it was concluded that the yeasts involved in biological aging belonged all to Saccharomyces cerevisiae, distinguishing four subspecies or physiological races: beticus, cheresiensis, montuliensis and rouxii. On the other hand, molecular techniques, which allow the characterization of oenological yeasts and discriminate between the different strains, are usually pulsed field electrophoresis (PFGE), the analysis of the polymorphism for the length of the restriction fragments (RFLP) of mitochondrial DNA, and multiplex PCR of microsatellites. Recent studies in our laboratory show the existence of at least 9 different genotypes of S. cerevisiae veil of flor species, based on the study of microsatellites (SSR-PCR). In addition, we have detected the presence of some species of non-Saccharomyces yeasts not described previously.