his study had two aims: to develop and compare yeast immobilisation processes with two wine-compatible supports (oak chips and cellulose powder) and to compare two yeast strains immobilised with these two processes to free yeasts in bottle fermented sparkling wine production.
- IOC18-2007 (Prise de Mousse) commercial yeast and Enolab55A (isolated from organic Spanish wine) were immobilised on oak chips and cellulose powder (Agrovin S.A.). Electron microscopy confirmed adherence of both yeast strains to the immobilised supports after lyophilisation.
- Vinification trials were conducted on a base wine containing 80% Macabao and 20% Chardonnay.
- The second fermentation was conducted according to the Champenoise method.
- A total of 135 bottles were fermented.
- No riddling agents (containing bentonite) were added.
- Bottles were kept at 11 – 13°C for 9 months.
- Riddling was conducted via an automated gyropallette and yeast sedimentation efficiency was determined by considering the total time the gyropallette required to render wines clear.
- Basic wine analysis, volatile aroma compound analysis and sensory analysis (16 experts) were conducted.
- Sugar consumption of the immobilised yeasts commenced one week after the fermentations conducted with the free yeast cells. All sugars of all fermentations were consumed within 60 days.
- The riddling process with the immobilised yeasts were three-fold quicker than the free cells with no riddling agent added.
- Significant differences were obtained in the titratable acidity between the different treatments.
- Significant differences were obtained in the volatile aroma analyses of the different yeasts and immobilised support.
- Yeast strain 55A released higher amounts of polysaccharides and produced more esters when immobilised on oak chips.
- Overall oak chips proved to be the more appropriate support.
- Despite measured chemical and volatile compound differences, no differences between treatments were observed in sensory analysis.
Significance of the study:
A new procedure to immobilise Saccharomyces cerevisiae sparkling wine yeasts on oak chips and cellulose (both accepted for use in oenology) was successfully developed. The use of such immobilised yeasts for second fermentation in the bottle does not alter the sensory profile and thus quality of the final wines. It provides winemakers the opportunity to riddle without bentonite.
Berbegal, C., Polo, L., García-Esparza, M.J., Lizama, V., Ferrer, S. and Pardo, I. (2019). Immobilisationof yeasts on oak chips or cellulose powder for use in bottle-fermented sparkling wine. Food Microbiology 78: 25-37. https://doi.org/10.1016/j.fm.2018.09.016