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Individual "terroir yeast strains" do not exist in vineyards. This is what French scientists have discovered. Isabelle Masneuf-Pomarède, oenologist and professor at Bordeaux Sciences Agro, says: "Saccharomyces cerevisiae do occur in vineyards - but only on one in 1,000 berries. You can select them and propagate them for fermentation. However, the concept of a 'terroir yeast' in the sense of a yeast strain that occurs exclusively in a particular plot or vintage cannot be scientifically proven."
Patrick Lucas, professor of oenology at the Institute of Viticulture and O enology (ISVV) at the University of Bordeaux, refers to a study by Jackson Peter at the University of Strasbourg. He studied more than 1,000 strains of Saccharomyces cerevisiae from different vineyard sites in Europe, North America and Asia. This study also clearly proves that there is no difference between the strains based on their geographical origin.
According to Isabelle Masneuf-Pomarède, the concept that microorganisms in the vineyard have an influence on wine quality arose from speculation in the course of American research. "From the finding that microbial communities varied depending on the growing area, the authors hypothesised that the microorganisms present in the soil and on the plant played an important role in the sensory characteristics of the wine." This turned out to be wrong, he says. Patrick Lucas points out that "winemakers who declare that they work with local or terroir yeasts are not arguing impurely. But fermentation microorganisms are not fixed to a particular region. We have recently seen how quickly a virus can be transported around the world. The same is true for yeast and bacteria. The entire European scientific community agrees with us".
(al / Source: vitisphere; Photo: 123rf - igorartmd)