Interaction between Cork and Yeast: Application to Sparkling Wine Processing

An innovative method has been developed to observe yeasts at the surface of cork using two-photon microscopy and to investigate if a removable crown cap substitution by a two-disc cork stopper may affect the bottle fermentation during sparkling wine processing. While much of the Champagne wine industry is using crown seals for tirage and aging, some producers are choosing cork closures, particularly for Champagne wines subject to longer aging periods. The developed technique is based on cork autofluorescence and on DAPI (4'6-diamidino-2-phenylindole) labeling of yeasts with a different emission wavelength range. This study was performed for cork in contact with model wine and in the bottle with Champagne wine, while following fermentation and maturation over one year. For both cases, neither biofilm nor strong adhesion of yeast cells was detected on the cork surface. However, in the case of Champagne wine, a small amount of yeast was observed in the empty cavities of the cork cell structure. The development of yeasts on the cork surface remains very limited, thus cork stoppers with discs can be used during Champagne wine processing without concern for cork as a potential fermentation support.