WINE TASTING

By KATHERINE COLE

Scientists tell us that birds and insects -- most notably, wasps -- deliver yeasts to grapes as they hang in the vineyard. Winery cellars, too, are teeming with yeast cells.

When crushed grapes macerate in an open vat at room temperature, these wild yeasts spontaneously launch the fermentation process. But from here, things can go awry. The juice could turn to vinegar; it could get "stuck" and only ferment halfway; or if it does go all the way to wine, it could be stinky and unpalatable. It's much less risky to avoid these pitfalls by killing off the wild yeast with sulfur dioxide, then inoculating the juice with a hardier strain of cultured yeast that isn't bothered by the sulfur and won't quit in the middle of fermentation.

Since the first commercial winemaking yeasts hit the market in the mid-1960s, many winemakers haven't looked back. With the ability to choose yeasts that complement the quirks of a particular vineyard, or the style of wine they hope to create, vintners can sculpt their wines by hand rather than trusting them to fate.

This boon has resulted in a backlash, of course. Over the past couple of decades, artisanal producers have embraced the "natural" winemaking movement, which calls for minimal cellar intervention in the manner of traditional family-run wineries in Europe's classic winegrowing regions.

As long as I've been covering wine in the Willamette Valley, I've known vintners who allow their wine to ferment spontaneously, trusting wild yeasts to do their thing. But when fermentations get stuck or a tank of pricey grapes starts to go south, do those winemakers reach for a yeast packet? You bet they do.

 

In fact, many producers experiment with both styles of fermentation, blending the two together. Winemakers tell me that spontaneous fermentation tends to be slower, building a more character-ful (and sometimes flawed) wine. Inoculating with cultured yeast results in a quicker fermentation and a cleaner wine, albeit one that might not be so soulful.

Oregon winemakers tend to be open-minded and curious about their work. So when I asked around to see who might be comparing wild with cultured-yeast fermentations, I received heaps of enthusiastic responses. Turns out that vintners all over the state are playing around with wild and cultured yeasts, hedging their bets by doing both. So we gathered up as many wines and winemakers as we could fit into the drop-dead-gorgeous private dining room at Penner-Ash Wine Cellars and went to work, tasting samples of wild-yeast wines against otherwise-identical cultured-yeast wines.

 

THE TAKE-AWAYS

1. Cultured and wild yeasts live up to their names. Overall, the wines that had been inoculated with cultured yeasts tasted more polished, linear, mineral and, in some cases, kind of uptight and boring. The native-yeast-fermented wines were unpredictable but more fun, with lively fresh fruit notes accompanied by quirky, funky characteristics that ranged from rustic to problematic.

2. Spontaneous fermentation is a total crapshoot. Wild yeast can create a more complex wine, or it can create a hopelessly flawed wine. Our group of winemakers agreed that if you're working with an imperfect or unknown batch of fruit, you're probably better off inoculating with a cultured yeast that you know will get the job done.

"That is a risk when you do native fermentation: You get this little extra activity, which can result in ethyl acetate or volatile acidity. Taken by itself, it's an issue. But blended with another lot, it can add a layer of complexity," says Lynn Penner-Ash.

"The behavior and metabolism of this whole microbial ecosystem is going to be much different than an inoculated fermentation, which is a much more controlled environment," adds Sarah Cabot.

 

3. Wild and cultured yeasts aren't so different, actually. "All commercial yeasts were originally in a wine cellar and were collected and propagated from there," points out Howard Mozeico. "So this whole conversation about 'wild' is sort of disingenuous." In fact, Sarah Cabot at Omero Cellars makes her own "wild" yeast by harvesting yeast cells from the skins of grapes hanging in her vineyard, because "completely uncontrolled ferments in the Carlton Winemakers Studio (where up to 12 producers work side-by-side) make me incredibly nervous."

4. Dogma is overrated. There's a group of critics and "natural" winemakers who preach that any vinous fermentation that's not spontaneous will result in overconstructed, inauthentic wines. Our group of winemakers wondered among themselves what these diehards do when fermentation gets stuck, threatening the viability of a whole vintage. "The issue is the honesty behind it," says Ron Penner-Ash. "Come on!"

5. For pinot noir, blending spontaneous and inoculated fermentations is a solid strategy. As our group tasted through wild- and cultured-yeast pinots side by side, we found that the two often complemented one another. "I'm very pragmatic," says Lynn Penner-Ash. "I have a hard time saying yeast or don't yeast." Ron Penner-Ash agrees: "They way I look at it, the yeasted wines are mentoring the non-yeasted wines. There is a mentorship, and you need both."

6. Wild-fermented riesling is a wine to watch. We loved the aromatics we got from the Love & Squalor riesling that had gone through spontaneous fermentation. It had aromas of "floral dried grass," according to Melissa Burr, and "apple skins -- that's a note I never get from cultured yeast," says Julia Cattrall. We've been reading a lot about the move toward wild yeast among riesling makers and we're excited to taste more of these intriguing wines.