atypical yeasts in winemaking linda f. bisson wine flavor 101b march 23, 2012
TRANSCRIPT
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
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• FrootZen™: Pichia •Metschnikowia MP346• Torulaspora delbrueckii
FrootZen™
•Viniflora® FrootZen™ 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 pulcherrima
Torulaspora
delbrueckii
Saccharomyces cerevisiae
Critical Value Difference
Newell-MacFarlane
10A 26AB 23AB 35B 26AB 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)
Conclusions
•No impacts on fermentation rate•Rhythm™ was the only yeast that
showed a significant difference from the Saccharomyces –only control