Assessment of dominance of added yeast in wine fermentation and origin of Saccharomyces cerevisiae in wine-making.

The source of Saccharomyces cerevisiae responsible for the natural fermentation of grape must and the dominance of added yeast in wine fermentations have been studied using a strain of Saccharomyces cerevisiae selected for wine-making and labelled for not producing hydrogen sulphide (H2S-) as fermentation starter.It was shown that the source of the Saccharomyces flora of fermenting musts was the winery itself and that a selected yeast starter added initially is able to impose itself on the spontaneous grape juice flora naturally.