Use of nitrogen compounds in spontaneous and inoculated wine fermentations.

In this paper the use of nitrogen compounds in garnacha must inoculated with active dry wine yeast Saccharomyces cerevisiae subsp. cerevisiae strain Na33 has been studied. The results are compared to garnacha must fermented with indigenous yeasts (control must). In the samples where the inoculated yeast predominated, no qualitative differences were appreciated in the use of amino acids with respect to the control samples, although there were quantitative differences. In the musts where the Na33 strain dominated, a lesser quantity of amino acids were consumed at the beginning of fermentation than in the control samples. For that reason, probably, this yeast showed problems in competing for the nitrogen nutrients of the must; this could have made its implantation in one of the inoculated samples more difficult. At the end of fermentation the Na33 strain continued to consume amino acids at high concentrations of ethanol. Its high tolerance to this toxic could be favored by the production and rehydration of dry wine yeast in the presence of air.