Yeast strain affects phenolic concentration in Pinot noir wines made by microwave maceration with early pressing

Aims: This study examined the effects of yeast strains in a novel winemaking process that had been designed to optimize phenolic extraction and improve production efficiency for Pinot noir winemaking.

Methods and Results: Microwave maceration with early pressing and co-inoculation of yeast and malolactic bacteria for simultaneous alcoholic and malolactic fermentation was investigated. Yeast treatments (Saccharomyces cerevisiae RC212 and EC1118, and Saccharomyces bayanus AWRI1176) were co-inoculated with Oenococcus oeni PN4 immediately after must microwave maceration. Alcoholic and malolactic fermentation were complete 17 days postinoculation for all three yeast treatments. At 16-month bottle age, the AWRI1176-treated wines had approximately twice the nonbleachable pigment and colour density of wines fermented by EC1118 and RC212.

Conclusions: The novel winemaking process produced Pinot noir wine that was stable 37 days after fruit had been harvested and yeast strain choice significantly impacted the stability and phenolic character of wine.

Significance and Impact of Study: Successful simultaneous alcoholic and malolactic fermentation in 17 days, and a demonstrated lack of inhibition between the yeast strains and malolactic strain applied in this study, provide proof of concept for very rapid red winemaking using the novel winemaking approach described herein. Further investigation would be required to assess strain effects on wine aroma, mouth feel and taste, however, this novel winemaking approach may offer significant industry efficiencies.