Effects of co-fermentation with Candida stellata and Saccharomyces cerevisiae on the aroma and composition of Chardonnay wine

Abstract

Effects of several inoculation protocols using Saccharomyces cerevisiae strain AWRI 838 (an isolate of Lalvin EC11 18) and Candida stellata strain AWRI 1159 (CBS 2649) upon the aroma properties and chemical composition of Chardonnay wine were determined. An increase in the concentration of glycerol and acetic acid was observed when fermentation was performed with C. stellata AWRI 1159, which did not progress to dryness. Sensory descriptive analysis showed a substantial difference in aroma between the wines produced by monocultures of the two yeast species. The Candida stellata AWRI 1159 produced significantly more intense ‘honey’, ‘apricot’, and ‘sauerkraut’ aromas, and diminished the ‘lime’, ‘banana’‘tropical fruit’ and ‘floral’ aromas ascribed to S. cerevisiae AWRI 838. When C. stellata AWRI 1159 was co-inoculated at ten times the initial concentration of strain S. cerevisiae AWRI 838, the non- Saccharomyces yeast had only a minor impact upon wine aroma and composition despite maintaining a significant viable population of 5–10 times 10⁶ colony forming units per mL throughout fermentation. Wine of a different aroma profile to either of the reference monoculture wines was produced by sequential fermentation, whereby C. stellata AWRI 1159 conducted the first half of fermentation, before inoculation with S. cerevisiae AWRI 838, and the subsequent completion of fermentation. This wine had ‘floral’, ‘banana’, ‘lime’, ‘tropical fruit’ and ‘sauerkraut’ aroma scores intermediate to the two reference monoculture wines, ‘apricot’ and ‘honey’ aroma ratings similar to the S. cerevisiae AWRI 838 wine, and ‘ethyl acetate’ aroma that exceeded that of both reference wines. These results suggest the potential of a reliable mixed culture fermentation strategy for exploiting unconventional, fermentation-impaired yeasts for producing greater flavour diversity in wine.