Atypical Yeasts in Winemaking Linda F Bisson Wine
Atypical Yeasts in Winemaking Linda F. Bisson Wine Flavor 101 B March 23, 2012
Grape and Wine Microbiota • Diverse numbers of yeast and bacteria are found on grapes • Persistence of microbiota depends upon: • Relative numbers • Permissive requirements for growth • Presence of inhibitory conditions
Uses of Atypical Yeasts • To complete fermentation (fructophilic Candida species) • To add nuances: Metschnikowia, Torulaspora, Pichia
Experimental Goal • We had a bad Chardonnay, low percentage of rot across most clusters • A “true” native would be risky under these conditions • Decided to assess impact of atypical yeasts under these high microbiota conditions
Two Types of Atypical Yeast Products • Sequential • Simultaneous
Sequential Products • Inoculate first with non. Saccharomyces yeast • At a specific later point in fermentation inoculate with Saccharomyces
Simultaneous Inoculation Products • Inoculate once, with a specific mixture of non-Saccharomyces and Saccharomyces yeast • Relative ratios impact persistence and duration of fermentation
Tested Three Different Yeasts with Sequential Addition • Froot. Zen™: Pichia • Metschnikowia MP 346 • Torulaspora delbrueckii
Froot. Zen™ • Viniflora® Froot. Zen™ consists of the yeast Pichia kluyverii in frozen form • Juice is inoculated with the Pichia strain, allowed to ferment to 4% v/v alcohol • Then inoculate with Saccharomyces to complete fermentation
Informal Sensory: Sequential • Students in class were able to differentiate all atypical yeast strains from native and inoculated fermentations post-fermentation • Differentiation was statistically significant, with the Metschnikowia fermentations showing the least significant differences with both the native and inoculated fermentations
Initial Preference Ranking Yeasts & Rank Totals Native Pichia kluyveri Metschnikowia Torulaspora Saccharomyces Critical pulcherrima delbrueckii cerevisiae Value Difference Newell. Mac. Farlane 10 A 26 AB 23 AB 35 B 26 AB 18 Highest Score Means Most Preferred
Simultaneous Inoculation Products • Based on adding specific mixtures of Kluyveromyces thermotolerans and Torulaspora delbrueckii • Viniflora®: Harmony™ (Saccharomyces, Kluyveromyces, Torulaspora), Melody™ (Saccharomyces, Kluyveromyces, Torulaspora) and Rhythm™ (Saccharomyces and Kluyveromyces)
Fermentation Profiles
Conclusions • No impacts on fermentation rate • Rhythm™ was the only yeast that showed a significant difference from the Saccharomyces –only control
Atypical Yeast Tasting • Glass 1: Saccharomyces control • Glass 2: Native control • Glass 3: Metschnikowia • Glass 4: Pichia (Froot. Zen™) • Glass 5: Torulaspora • Glass 6: Rhythm™ (Kluyveromyces)
- Slides: 16