Say the word “Brettanomyces” in a room full of booze hounds, and you’ll be either applauded or shunned. Beer geeks of a certain stripe can’t get enough of this wild yeast, nicknamed “Brett” and featured in limited-edition bottles by breweries like Allagash and The Bruery.
Brett elicits a very different reaction in wine-drinking circles, however. Natural wine lovers might champion it, but the Court of Master Sommeliers classifies Brettanomyces as a wine fault in its deductive tasting format, right next to dreaded wine-killer TCA, or cork taint.
So what is Brettanomyces, anyway: creator of cult beers, or enemy of fine wine?
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A wild yeast that grows on the skins of fruit, Brettanomyces is most commonly associated with rustic, funky notes like barnyard, stinky feet, and manure. Should Brett accidentally appear during the wine- or beer-making process, it could induce an unwanted secondary fermentation, making the beverage unstable and adding unwanted flavors. Kris Matthewson of Bellwether Wine Cellars in the Finger Lakes once recollected his father-in-law’s moment of panic upon discovering Brett in a vat of aging cider; he immediately hauled the cider, barrel and all, into the woods.
While Brettanomyces has historical significance in both wine and beer — it was commonly, if unintentionally, found in famous wines like Bordeaux and Châteauneuf-du-Pape until the early 1990s, and it was actually first discovered when researching the spoilage of English ales — each industry’s modern reaction to the yeast has been markedly different.
Brewers purposefully integrate Brett. Modern Brett beers are made using the slow-fermenting yeast from start to finish, creating unique, complex flavors and aromas.
“With the innovation craft brewers started bringing to the brewing world, these brewers began to look more towards historic beers,” explains Chad Yakobson, owner and brewer of Crooked Stave Artisan Beer Project in Denver, which specializes in Brett beers. “That is when wild and sour beers started to become a huge draw, largely in part because of the wild yeast Brett.”
But while some winemakers, like Chris Howell of Cain Vineyard & Winery in the Napa Valley’s Spring Mountain District, are becoming more open-minded about the potential positive effects of Brett, it still causes a knee-jerk reaction for most wine pros. With the exception of trendy yet divisive natural wines, most winemakers have been taught to scrub their cellars nearly sterile over the past 25 years to guard against the “B word.”
“Today when you talk to people in the world of wine, you’ll hear talk about the vineyard or terroir, but they’ll downplay the vinification,” Howell says. “If the highest value in wine is the terroir, then anything you do in the cellar that obscures the terroir is a problem.” Brewers, on the other hand, tend to highlight the manual aspects of their processes, not just where they sourced their grains.
“The thought is that a yeast with a strong personality could somehow erase or override the terroir of the wine because of its characteristics,” Howell says. “Wine is only focused on killing Brett, not understanding it.”
Another problem Brett introduces to winemaking is unpredictability. Slow-fermenting Brettanomyces yeast can continue to work for years after bottling, meaning wine could become unstable or develop alternate tastes as it ages.
Understanding is a worthwhile pursuit, however, as the success of Brett beers has demonstrated. Removing Brett’s stigma could lead to a wider range of more complex and interesting wines.
“Brett is truly an amazing yeast when used skillfully,” Yakobson says. In addition to earthy or funky notes, Brett can also create such floral flavors as rose and violet, hints of clove, and umami. Yakobson notes that Brettanomyces adds structure to Crooked Stave’s citrus and tropical fruit notes, making the beers actually more stable over time.
Even those who embrace Brett’s positive attributes stress the need for balance. While Brettanomyces can be part of a wine’s natural character, it can also easily overwhelm it. Components like Brett should complement terroir, not replace it entirely.
“If the Brett becomes the definition of the wine then we’ve lost the point,” Howell says. “Brett can be part of the story, but it’s not the story.”