Influence of the yeast strain on Monastrell wine colour

Two commercial yeast strains were assayed during the winemaking process of Monastrell grapes to determine their influence on colour and phenolic composition of the resulting wines during alcoholic fermentation and maturation. The results showed that in 2002, the wines did not present great differences but in 2003 higher colour intensity and phenolic compounds content were detected when one of the commercial strains was used. A discriminant statistical analysis clearly showed that different yeasts led to different wines as regard their chromatic characteristics.Industrial relevanceThe importance of yeast in winemaking is extensively known since they are responsible for the transformation of sugars into ethanol and for the formation of the most significant aroma compounds in wines. However, they may also participate in wine colour and this role is usually not taken into account in the wine industry. The choice of a yeast strain is an important factor since these microorganisms have the capacity to retain or adsorb phenolic compounds and, on the other hand, yeast may contribute to stabilizing wine colour, as a result of participating in the formation of vitisins during fermentation or liberating mannoproteins that have the capacity to bind to anthocyanins and tannins, protecting them from precipitation. Two commercial yeast strains were assayed during the winemaking process of Monastrell grapes to determine their influence on colour and phenolic composition of the resulting wines during alcoholic fermentation and maturation. The results showed that higher colour intensity and phenolic compounds content were detected when one of the commercial strains was used, both during fermentation and wine aging, and may be used as a tool during winemaking for obtaining stable and highly coloured wines.