Aim Among the most important factors influencing wine quality are yeast strains and fermentation temperature. Fermentation at low temperature is presently used in winemaking to improve both aroma formation and retention. In this study, we have analysed the oenological characteristics of Tempranillo wines produced at 12 and 28°C by different Saccharomyces species and hybrids. Methods and Results Low temperature had a strong influence on yeasts fermentation kinetics, increasing fermentation times to more than 2 weeks. In some strains, glycerol production seemed to be positively influenced by low fermentation temperature. Analysis of the aroma composition of wines produced by different Saccharomyces species and hybrids revealed large differences depending on fermentation temperature. Conclusions Higher alcohols production seemed to be dependent on the strain. Production of acetate esters seemed to be favoured at 28°C, whereas production of ethyl esters was apparently preferred at low fermentation temperatures. The best aroma producers at 28°C were Saccharomyces cerevisiae strains, whereas Saccharomyces uvarum and some hybrids excelled at 12°C. Significance and Impact of the Study Our results suggest that fermentation temperature and yeast species are of crucial importance for production of metabolites influencing wine aroma.

Consumer wine preferences are changing rapidly towards exotic flavours and tastes. In this work, we tested five non-conventional yeast strains for their potential to improve Ribolla Gialla wine quality. These strains were previously selected from numerous yeasts interesting as food production candidates. Sequential fermentation of Ribolla Gialla grape juice with the addition of the Saccharomyces cerevisiae T73 Lalvin industrial strain was performed. Zygosaccharomyces kombuchaensis CBS8849 and Kazachstania gamospora CBS10400 demonstrated positive organoleptic properties and suitable fermentation dynamics, rapid sugar consumption and industrial strain compatibility. At the same time, Torulaspora microellipsoides CBS6641, Dekkera bruxellensis CBS2796 and Dekkera anomala CBS77 were unsuitable for wine production because of poor fermentation dynamics, inefficient sugar consumption and ethanol production levels and major organoleptic defects. Thus, we selected strains of K. gamospora and Z. kombuchaensis that significantly improved the usually plain taste of Ribolla wine by providing additional aromatic complexity in a controlled and reproducible manner.