Generation of yeasts that intensify floral aromas in wine

Across the wide range of commercial yeast strains available to winemakers, there is substantial variation in their production of aroma compounds.

Some desirable compounds are not typically produced at high enough concentrations to make a difference to wine aroma and flavour.

Examples include the yeast-derived compounds 2-phenylethanol (2-PE) and 2-phenylethyl acetate (2-PEA), which are associated with ‘rose’ and ‘floral’ aromas in wine.

Generally, the concentrations of these ‘rose’ aroma compounds in wines are below their aroma sensory thresholds, particularly in white wines, so their potential contribution to wine aroma is considered to be minimal.

By using classical yeast strain development techniques, more than forty non-genetically modified (non-GM) yeasts that produce high concentrations of both ‘rose’ aroma compounds 2-PE and 2-PEA were generated at The Australian Wine Research Institute (AWRI) (Cordente 2018). These ‘rose’ yeasts were isolated from three different parent Saccharomyces cerevisiae strains, with each having different fermentation volatile profiles and competitive fitness characteristics that might suit different winemaking styles.

After a brief description of the interesting techniques applied in this study, Toni Cordente describes the pilot scale trials carried out over the last four vintages to assess wine styles that may be compatible with enhanced ‘rose’ aroma characteristics, including white, rosé, red and sparkling wines.

In these trials, different applicational aspects were evaluated, such as the relationship with other compounds derived from fermentation, the evolution of 2-PE and 2-PEA concentration over time and the effect that their different concentrations may have on the olfactory characteristics of the wine, as well as the possibility of adjusting the concentrations according to specific wine styles,