Influence of grape treatment on the wine yeast populations isolated from spontaneous fermentations

AIM: To study the influence of different methods of grape treatment in wineries on the diversity of the yeast species in spontaneous fermentations. METHODS AND RESULTS: Grapes were crushed and pressed in three different ways followed by spontaneous fermentation. The same grape material picked and crushed aseptically directly in the vineyard served as control. Yeasts isolated at different stages of the fermentation were characterized by 5.8S-ITS-RFLP. Yeasts of the Saccharomyces sensu stricto complex were additionally analysed by microsatellite polymerase chain reaction fingerprinting. The diversity of yeast species isolated from winery fermentations was much greater than from the vineyard fermentation in respect to yeasts of the genus Saccharomyces as well as non-Saccharomyces. CONCLUSIONS: Oenonogical methods alter significantly the yeast diversity in spontaneous fermentations of grape juice. SIGNIFICANCE AND IMPACT OF THE STUDY: Managing spontaneous fermentations successfully depends not only on choosing the suitable grapes but also on the crushing and pressing techniques leading to different yeast populations.