What yeast does a fine wine company use?

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A crucial component in winemaking is the yeast that actually carries out the fermentation of the alcohol - but what strains of yeast does the typical fine wine company use?

The answer is that the yeasts used all over the world are surprisingly similar, according to genetic analysis carried out by the Australian Wine Research Institute and published by the Genetics Society of America.

Saccharomyces cerevisiae is the yeast generally used in winemaking, as it is better able to withstand the acid levels in the original grape juice, which mean the yeasts used in beer and bread would not survive.

But after analysing 212 different strains of the yeast, scientists found that all of them were very nearly identical, and any genetic diversity was likely due to hybridisation with other yeasts, such as those used in brewing.

That doesn't mean that every fine wine company uses an identical yeast though - for instance in four strains, a unique set of genes were detected, and these give wines fermented by those yeasts a unique aromatic quality.

Anthony Borneman, lead author on the paper from the Australian Wine Research Institute, said: "It takes a tough yeast to ferment wine. Wine yeast need to be far more stress tolerant than strains used in brewing or baking, for example, to cope with the very high sugar and acidity levels of grape juice.

"Our results show that only a limited branch of the yeast evolutionary tree is currently used in winemaking."

The findings provide some insight into the origins of the different commercially available wine yeasts - for example, nearly all premium champagne yeasts seem to share the same common ancestor - and may help to develop new variations for the future, allowing the winemaking process to evolve into new territory thanks to new genetic diversity in the yeast that is used.