Yeasts Isolated from Pellicle on the Surface of Wines

Studies on Pellicle Formation of the Yeast Strains on Wine (Part II)

Abstract

Thirty strains of film yeast were isolated from 24 samples of pellicle on the surface of wines during storage. The used samples were obtained from both the young wines stored within 6 months and the old wines stored for 6 months to 3 years in 12 wineries in Yamanashi Prefecture.
Among these strains isolated, 21 strains, in which 5 strains were from the young wines and 16 strains were from the old wines, were identified as pseudo-film yeast of genus Saccizaromyces. The other 9 strains, in which 7 and 2 strains were from the young wines and the old wines respectively, belonged to true film yeast (Hansenula, Pichia, Candida).
Influence of ethanol, SO₂ and variety of grape on pellicle formation of the isolated film yeasts was then examined. On the surface of the wines containing 12. 2 vol.% of ethanol and/or above 80 ppm of SO₂, The moderate to abundant pellicle was formed by almost all strains belonging to Saccharomyces, while pellicle was scarcely formed by true film yeast strains.
Further, the red wine (Cabernet Sauvignon) was more favorable for pellicle formation than the white wine (Koshu).
It was pi-essurned from the latter evidence that a pellicle-response factor might present in wines.