Influence of the production yeast strain on the development of malolactic fermentation in white wine

The aim of the research was to study the influence of the hybrid strain of Saccharomyces 12233 x 6167, its parents - Sacch. bayanus 12233 and Sacch. cerevisiae 6167 - and the control strain Sacch. cerevisiae 220 on the growth of lactic bacteria in white wine. A number of winemaking cycles with three samples of must from white grape of typical Sicilian and Calabrian cultivars were carried out without the addition of SO2 At the end of fermentation the wines were clarified and bottled, both with and without the addition of SO2. The wines were stored at 15-20 degrees C for 90 days. The wines showed different levels of malic acid degradation as influenced by their ethanol content, the yeast strain used as a starter, and the levels of residual SO2. The results demonstrate that the wines produced by the Sacch. cerevisiae strains were essentially unable to inhibit the start of malolactic fermentation, except when 80 mg/L of SO2 were added to the wines. On the other hand, all the wines produced by the Sacch. bayanus 12233 effectively prevented the growth of lactic bacteria with just 40 mg/L of SO2 and, for one cultivar, also without the addition of SO2. The wines produced by the hybrid strain of Saccharomyces had an intermediary behaviour; therefore, with a low addition of SO2, this strain stabilises white wines and prevents an excessive production of acids. This system of white wine microbiological stabilisation reduces SO2 and offers considerable advantages for the health of the consumer.