Construction of hybrid yeasts with increased flocculation for white wine manufacture

Hybrid strains of yeast have been selected that have better flocculating properties for white wine manufacture. The hybridisation of the production winemaking strain 13a (Varna 84) with a Saccharomyces cerevisiae haploid strain carrying the FLO5 mutation resulted in a hybrid with very good flocculation ability. Its fermentation activity was increased using several backcrosses. At the final step two meiotic segregants with mating ability were crossed with the production wine-manufacturing strain 75b (Sofia 75); hybrids K93 and K97 were obtained. These hybrids showed better flocculation ability and a more rapid fermentation in comparison with the parental strains 13a and 75b. The composition, taste and aroma of wines obtained using hybrids were similar to those produced by parental strains. The treatment of young white wines was easier if constructed hybrid strains were used.