The aim of the study was to evaluate the impact of a vineyard-derived pied de cuve (fermentation starter culture) compared to spontaneous and commercial yeast inoculated fermentations, on the microbial, chemical and sensory characteristics of wines.
PROJECT LAYOUT
- Two pied de cuves were prepared from Ugni blanc and Sauvignon blanc grapes four days before the harvest.
- After fermenting two days at 20˚C ammonium phosphate and thiamine were added to the two 12 litres of must.
- Temperatures and sugar concentrations were measured daily.
- After 30 – 50% of alcoholic fermentation completion the pied de cuves (PdCs) were subjected to microbial, chemical and sensory analyses.
- The PdCs were then inoculated into 225L barrels containing cold settled Sauvignon gris juice.
- Two additional barrels of the same Sauvignon gris juice underwent spontaneous and commercial yeast inoculated (Zymaflore X5) fermentations.
- Microbial, chemical and sensory analyses were performed on all the barrels.
MAIN RESULTS
- Zymaflore X5 finished fermentation first after 11 days.
- The spontaneous fermentation finished last after 17 days.
- The two S. blanc PdCs finished after 12 and 13 days respectively.
- One Ugni blanc PdC finished fermentation after 13 days and the other one after 18 days.
- The PdC with the longest fermentation time also had the highest VA – 0.61 g/L.
- X5 and one S. blanc PdC had the lowest sulphur production – 9 mg/L total SO2.
- The spontaneous fermentation had the highest sulphur production: 38 mg/L total SO2.
- The other PdC’s ranged between 10 – 15 mg/L total SO2.
- Descriptive sensory analysis did not reveal any significant differences between the wines.
- Microbial analysis of the PdCs indicated dominance by non-Saccharomyces yeasts, with S. cerevisiae quite rare. S. cerevisiae numbers increased after inoculation into the barrels.
- Microbial analysis of the spontaneous fermentation showed high S. cerevisiae diversity, meaning many S. cerevisiae strains taking part in the fermentation.
- The S. cerevisiae populations differed between the different PdCs as well as the spontaneous fermentation.
SIGNIFICANCE OF THE STUDY
In this study three of the four PdCs were as efficient as the commercial yeast to complete fermentation and produced sensory results similar to the commercial yeast. Even though the study was done on small scale in a very specific setting, it does provide some evidence that indigenous yeast PdCs could potentially be a more secure option than spontaneous fermentations.
REFERENCE
Börlin, M., Miot-Sertier, C., Vinsonneau, E., Becquet, S., Salin, F., Bely, M., Lucas, P., Albertin, W., Legras, J.-L., & Masneuf-PomarèdeI. (2020). The “pied de cuve” as an alternative way to manage indigenous fermentation: impact on the fermentative process and Saccharomyces cerevisiae diversity. OENO One, 54(3), 335-342. https://oeno-one.eu/article/view/3105
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