Dynamics and diversity of non-Saccharomyces yeasts during the early stages in winemaking

This detailed study observed the yeasts present in the ecological niche of “wine must”. The dynamics and identity of non-Saccharomyces yeasts during the cold maceration and alcoholic fermentation of grape must were investigated under real production conditions in the Bordeaux region. Furthermore, we studied the impact of two oenological parameters on the development and diversity of non-Saccharomyces yeasts during cold maceration: temperature management and the timing of dried yeast addition. n-Saccharomyces community underwent constant changes throughout cold maceration and alcoholic fermentation. The highly diverse non-Saccharomyces microflora was present at 104–105 CFU/mL during cold maceration. The population increased to a maximum of 106–107 CFU/mL at the beginning of alcoholic fermentation, then declined again at the end. The population at this point, evaluated at around 103–104 CFU/mL, was shown to be dependent on the timing of yeast inoculation. The choice of temperature was the key factor for controlling the total yeast population growth, as well as the species present at the end of cold maceration. Hanseniaspora uvarum was a major species present in 2005 and 2006, while Candida zemplinina was very abundant in 2006. A total of 19 species were isolated.