Yeast strains role on the sulphur dioxyde combinations of wines obtained from noble rot and raisining grapes

Abstract

The influence of four industrial and indigenous yeast strains on the sulphur dioxide combinations of wines obtained from noble rot and raisining grapes is studied in different growth of the Sauternes area and one growth in the Jurançon area. The analysis of ketonic compounds (pyruvic acid and 2-oxo-glutaric acid), acetaldehyde and PC50 on the wines clearly showed significant statistical difference between the yeast strains for the sulphur dioxide combination. By adding the same dosage of sulphiting, the free SO₂ levels are variable depending on the yeast strain used. One strain (Zymaflore ST), isolated from a spontaneous fermentation of a botrytised must, giving wines with low PC50 values, is well adapted for the noble rot must vinification. The choice of the yeast strain is a parameter of importance to limit the sulphur dioxide amount in the wines.