Selection and implantation study of an indigenous red-wine yeast in Northpatagonia Argentina

LOPES C; BARBAGELATA R; GIRAUDO MR; CABALLERO A

Villa Carlos Paz

Congreso; XXXVIII Reunión Nacional de la S.A.I.B; 2002

The addition of yeasts to musts ensures the proper starting and conducting of alcoholic fermentation and best results can be obtained with selected yeast starters originating from the microarea where wines are produced.  In order to select an indigenous starter culture for northpatagonian red wines, three autochtonous Saccharomyces cerevisiae yeast strains -previously selected  and molecularly identified from a set of 58 on the basis of a wine yeast selection protocol- were compared on laboratory-scale fermentations (5L) at 27±2°C to asses their effects on physico-chemical parameters, volatile compounds and sensory analysis of Malbec wines. Fermentations with two commercial strains were used as controls. According to the results (ej. Maximum Fermentation rate, lowest volatile acidity and high alcohol levels), one strain named MMF9 was selected to be evaluated on other two red musts (Merlot and Cabernet Sauvignon) in which similar results were obtained. The implantation study  using the selected strain was performed on Cabernet Sauvignon red must inside 200L and 9000L tanks at 27±2°C. Fermentations with the best commercial strain and without any inoculum (natural) were performed as controls. Samples were taken periodically during fermentations for the isolation, enumeration and characterization of yeasts. Strains of S. cerevisiae were differentiated according to their killer biotyping. Resulting wines were analyzed as previously described. The selected indigenous strain are important contributors to the wine fermentations, and  wines obtained presented differential characteristics.