Use of nitrogen compounds in spontaneous and inoculated wine fermentations

In this paper the use of nitrogen compounds in garnacha must-inoculated wit h active dry wine yeast Saccharomyces cerevisiae subsp. cerevisiae strain N a33 has been studied. The results are compared to garnacha must fermented w ith indigenous yeasts (control must). In the samples where the inoculated y east predominated, no qualitative differences were appreciated in the use o f amino acids with respect to the control samples, although there were quan titative differences. In the musts where the Na33 strain dominated, a lesse r quantity of amino acids were consumed at the beginning of fermentation th an in the control samples. For that reason, probably, this yeast showed pro blems in competing for the nitrogen nutrients of the must; this could have made its implantation in one of the inoculated samples more difficult. At t he end of fermentation the Na33 strain continued to consume amino acids at high concentrations of ethanol. Its high tolerance to this toxic could be f avored by the production and rehydration of dry wine yeast in the presence of air.