Article by Palate Press

I feel as though I need to whisper this, but I think that yeast might be trendy. The furor (both supportive and critical) over natural wine is bleeding over into an interest in the “wild” yeasts that contribute to their distinction, and whether or not they’re really “wild.” Meanwhile, a super-saturated wine market means that producers are always and ever looking for ways to distinguish their product. Sometimes that means wrapping the bottle in paper or tying a twig around the neck or blending carbonated Moscato with vodka. But sometimes it means employing new and different yeasts to “add complexity” and finding a flavor profile that lies on the (hopefully) delicious edges just outside our genre expectations for grape and region.

Yeast have had a banner year. Last month, “microbial terroir” made the news when a beautiful paper from a team at UC Davis confirmed that microbes found in the vineyard change with location and climate; in other words, differences in vineyard microbe communities might contribute to differences in regional terroir. (The media largely overstated the conclusions of this study – the scientists haven’t yet linked differences in microbes to differences in flavor, but that’s the next step.) Earlier in 2013, the same folks made a microbe map of Davis’s student winery: they used DNA sequencing to identify every yeast and bacteria they could find on everything from the fermentors to the winery floor before, during, and after harvest. They found that, yep, the fermentation workhorse Saccharomyces cerevisiae hangs out year-round on winery surfaces (along withHanseniaspora uvarum, one of those other yeasts that can be part of the first few days of a spontaneous fermentation before Saccharomyces takes over). Those findings are important because they back up the long-standing belief that wineries have yeasts-in-residence that will show up in fermentations whether the winemaker deliberately put them there or not.

Looking out for the little guys

Like Pope Francis and Miley Cyrus and GMO salmon and most other organisms that make the news, yeasts have been talked up in large part because they’re controversial. The natural-winemaking-is-meaningless camp has gotten a lot of mileage out of findings like that microbial winery map and other research showing that the yeasts that finish up fermentation are rarely the ones that the winemaker chose, purchased, and dumped into the vat. These findings say that winemakers don’t have much control: if a highly competitive commercial yeast is in the winery environment (maybe because it was used in a previous year or a different wine), it’s going to end up everywhere. If natural winemakers wax poetic about the complexity added by their unique, homegrown microbe communities that arise organically out of vineyard, but the yeast in their vats is mostly some old commercial variety that comes freeze-dried by mail-order, are they just delusional?

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