When Yeasts Run Wild
Fashion aside, do indigenous yeast fermentations improve wine quality?
To steal a term from the social media world, wild yeasts are trending. More and more wines are being fermented with these yeasts (also commonly referred to as indigenous or native), rather than with ones cultured in a lab and purchased from a catalog.
The very phrase conjures up images of yeasty bacchanalias, wherein the wild yeasts gather in colorful tribal garb, and dance to primal rhythms while preparing for a really hot time in the old wine vat.
Designer yeasts, which parade down the runway in carefully styled attire, promise to bring known attributes to the finished wine. The wild bunch lets nature takes its course, as winemakers stand nervously by, hoping that there will be more interesting flavors and more complexity in the resulting wines.
As a wine critic, I am most interested in what I can actually taste. If wines made using wild yeasts taste better, then I’m all for them. I have no ax to grind about whether such wines are truer, cleaner, more honest or authentic. I just want to see if I can taste something discernible—and desirable—in terms of wine quality.
At least as far as the Oregon and Washington wines I’ve tasted, they often do seem more complex and interesting, though less mainstream.
In order to balance my admittedly subjective opinion, I conducted an informal poll online, asking winemakers who had worked with wild yeasts to discuss the potential risks, advantages and benefits.
I wondered if winemakers could describe something in the scents and flavors of naturally fermented wines that may be identified as specific to this approach.
Among the wineries who replied and said that all or most of their fermentations were done wild were Amalie Robert, Array Cellars, Boedecker Cellars, Miner Family, Pacific Rim and 21 Cellars.
Riesling, Chardonnay, Sauvignon Blanc, Sémillon, Pinot Meunier, Pinot Noir and Syrah were all cited as grapes that responded well to this approach. Advantages cited were greater aromatic complexity and increased diversity of flavors.
Specifically, one winemaker noted, you should “look for slightly higher-toned aromatics and a less monolithically fruity mid-palate.”
Said another, “our wines are not burdened by a commercial yeast strain that was selected to provide a certain flavor/aroma character at the expense of all other flavor and aroma compounds.”
There are dozens of commercial (designer) yeasts that offer significant safety advantages throughout the winemaking process. And there are yeasts with additional benefits, which promise to deliver certain style characteristics.
Peruse a yeast vendor’s Web site, and you’ll find a dizzying variety for sale. Some are designed for specific grapes, some for enhancing spice notes, and others for reducing herbaceousness, for production of fruity aromas or for accentuating volume in the mouth. Still others target such things as better tannin structure, color stability, alcohol tolerance and ageability.
There is nothing wrong with this, but the question remains, do wild yeasts deliver more interesting, if somewhat unpredictable, scents and flavors?
I find that native fermentations of white wine grapes seem to yield more complex floral aromatics, and meld together elements of citrus and stone as well.
I do not detect such specific results in red wines, perhaps because aging in new oak barrels tends to obscure those nuances. That said, native yeast fermentations of red grapes might bring other advantages, less obvious except to the winemakers themselves.
“We source three Cabs from top vineyards,” one wrote. “With lab yeast, all could be engineered to taste similar, but with native yeast, all three are distinctive, which is important when releasing vineyard-designated wines. You are getting a more true expression of the vineyard.”
As with most winemaking decisions, there is no ironclad right or wrong way to ferment. At the end of the day, it all comes down to what’s in the bottle, how those wild yeasts performed—and did you enjoy the show?