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The question

What does it mean for a wine to be “native yeast fermented?”

The answer

You’ll find words to that effect increasingly applied to wine labels these days. It means the wine maker relied on yeasts naturally found on grape skins and in the local air to ferment the juice. Put another way, no commercial yeasts were added.

That’s how wine was made for thousands of years, of course. In fact, invisible yeasts that normally reside on the skins of fruit were what permitted humans to discover fermentation in the first place. Fruit either rotted or was intentionally crushed. Then the surface yeasts made contact with and would begin feeding off sugars in the pulp of the fruit, producing alcohol and carbon dioxide.

But in modern times, most wine producers inoculate their juice with commercially isolated yeast mixtures. Analagous to the Fleischmann’s yeasts used by home bakers, these carefully selected fungal populations perform more reliably and predictably, minimizing the risk of, say, a stalled fermentation, which can spoil a wine’s quality. These fast-acting lab yeasts also come in various formulations that can enhance the desired flavour or aromatic profiles. For example, there are yeasts that contribute more of a pineapple note to a chardonnay and some that can amplify the natural passionfruit note in a sauvignon blanc.

Increasingly, however, craft-oriented producers have been turning to the old ways with “native” or “wild” or “indigenous” yeasts. (I should add that many producers have always relied on the natural method without ever advertising the fact.)

Proponents, and I’m among them, argue that wild yeasts can often result in a more complex or nuanced flavour profile, much in the way wild-fermented sourdough bread compares to a plain sandwich loaf, sometimes even helping to contribute the “minerally” note that is so prized today by wine aficionados.

At the very least, the use of native yeasts generally indicates that the wine maker cares enough to take risks in order to produce a wine that is arguably more locally authentic or idiosyncratic. Yeast, too, is part of terroir.

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