Ecology of spontaneous fermentation in one winery during 5 consecutive years

The ecology of spontaneous fermentation in a new winery in La Rioja (Spain) was studied during 5 consecutive years using mitochondrial DNA restriction analysis. The number of different strains detected for each vintage and their appearance frequency varied from one year to another. A small number of strains were present in consecutive years, but the presence of each one varied in function of the specific year. Only one strain was present in all the 5 years studied. For the 1997 vintage, an unusual dominance of non-Sacharomyces yeasts in the vigorous fermentation was detected; this may explain the abnormal analytical data for the wines of that year.