How Winemakers Use Native and Commercial Yeast to Craft Their Wine

Speaking with a winemaker recently and asking about indigenous yeast, she cut us off and asked why she would leave a major decision about her winemaking—fermentation—up to chance. When we delve into what goes into making a particular wine, enologists often talk about their yeast program, including the decision to use native yeast that is living on the skins of their grapes or chose a different strain of yeast to achieve a specific fermentation target. Grapes are the primary ingredient in winemaking and the choice of yeast can be equally important, but until somewhat recently in wine’s 8,000-year history winemakers were completely at the mercy of the elements including the type of yeast that was already on their grapes and in their winery.

How Many Types of Yeast Are There?

Single-celled microorganisms that are members of the fungus kingdom, yeast has been around for 100 million years, with 1,500 species recognized. Of these, the yeast that is most commonly used in winemaking is Saccharomyces cerevisiae, of which there are upwards of a thousand different strains. Scott Laboratories, one of the leading suppliers to the American wine industry, offers 90 different strains, each one offering a descriptive of the type of winemaking it is most suited for, where it originated, and details such as the type of aromas it can bring out in a wine. Other strains that naturally occur on grapes and in the vineyard are Kloeckera, Pichia, and Candida, and for better or for worse Brettanomyces may live on winery surfaces and participate in the fermentation process. In addition to wine, Saccharomyces cerevisiae is also used in bread baking, making cider and ale, and biofuel production—and has medical applications as well.

What Is the Benefit of Not Adding Yeast?

According to winemakers, the most important reason to use native, indigenous, or naturally occurring yeast (all the same thing) is to make a complex wine that showcases its terroir. Adam Lee, owner and winemaker of Clarice Wine Company, who made Robb Report’s Best American Pinot Noir in 2023, offers another good reason: It’s cheap. “Why would I spend money on something that I don’t need?” he asks, only half joking. On a more serious note he says, “Adding yeast isn’t something that I’ve found necessary for the wines I make from the Santa Lucia Highlands.” Although he hasn’t personally performed any side-by-side trials of his own wines using native and added yeast, Lee cites several studies he has read that show that the multiple strains of yeast present in spontaneous fermentation lead to a more complex wine.

Noted winemaker and consultant Paul Hobbs utilizes indigenous yeast for his Alvaredos-Hobbs Godello from the Ribeira Sacra region in Galicia, Spain. “We chose native yeast fermentation for our Godello because it results in a more nuanced and expressive wine,” Hobbs says. Native yeasts tend to ferment more gently than cultured strains, he says, creating a finer, more delicate foam layer without the aggressive bubbling you often see with commercial yeasts and that the slower pace of fermentation helps preserve the wine’s subtle esters and aromatic complexity, contributing to greater depth and vibrancy. “While cultured yeasts can lead to cleaner, more predictable fermentations, they tend to be more monochromatic, lacking the layered character that indigenous yeasts bring,” he says.

In the Uco Valley in Argentina’s Mendoza region, Zuccardi owner and winemaker Sebastián Zuccardi says that he uses spontaneously occurring yeast to achieve the “utmost transparency and purity” in his wines, including his top-tier Finca Piedra Infinita Malbec. Working with 100 percent native yeast across his whole portfolio, Zuccardi wants his wines “to tell the story of this unique landscape at the foothills of the Andes mountains.” He firmly believes that native yeasts contribute greater complexity and a stronger sense of place to the finished wine.

One of the most celebrated Napa Valley Cabernet Sauvignons in the world, Lokoya has received an almost unbelievable 17 perfect 100-point scores, which is more remarkable when one realizes that winemaker Chris Carpenter almost always uses only native yeast in its production. While Napa Cab may be considered by some to be the exact opposite of what proponents of the natural wine movement espouse, Carpenter’s collection of four AVA-designate wines from high elevation vineyards are made in a decidedly low-intervention style. Making wines that he calls “reflective of place,” Carpenter explains that each vineyard has its own environment that creates a unique set of growing conditions for the vines, giving his different expressions, whether from Mt. Veeder or Diamond Mountain its own signature of flavor that extends beyond the effects of soil, altitude, and seasonal conditions.

Is Adding Yeast Bad?

Although selection is the most important part of the winemaking process, Lisa Evich, winemaker at Sebastiani Vineyards and Chateau St. Jean in Sonoma says “the key to making quality wines is choosing a wine yeast that has been selected for the specific characteristics for your fermentation conditions.” Evich uses a yeast strain that is cold tolerant to retain aromatics and fruitiness when she is making Sauvignon Blanc and one that is suitable for ambient temperature barrel fermentation to achieve ideal mouthfeel and texture when producing Chardonnay. For a high-end red wine like Sebastiani Cherryblock Cabernet Sauvignon, she prefers a yeast strain that is adapted to fermenting at warm temperatures that is also a “vigorous fermenter” and is alcohol tolerant, “so it won’t give up in the end when there is still sugar left to ferment.”

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While Evich agrees that native yeast can produce interesting and complex flavors and mouthfeel, she says that if it’s not present in high enough quantities, it may not be strong enough to ferment to dryness, meaning that there will be residual sugar in what is intended to be a dry wine. Except for Zuccardi, all of the winemakers we spoke with add yeast either to specific wines or when necessary. Hobbs uses cultured yeast for his Crossbarn Chardonnay from Sonoma because it ferments faster, allowing the yeast to perform a specific role tailored to the needs of the wine. When Lee was still winemaker at Siduri, he used a yeast strain native to Barolo to provide earthiness and balance to Pinot Noir grown on young vines, which he thought would otherwise have been too fruity, and he also uses it for Sauvignon Blanc and Chardonnay under other labels. In certain vintages, Carpenter has inoculated up to 20 percent yeast to help boost what Mother Nature has provided. “When I think a vineyard is being impacted in ways that overly strain the vines, I’m a little less apt to allow for native fermentations,” he says, citing causes such as too much water during a wet season, bird damage, or seasonal lack of nutrients.

Whether naturally occurring or added by the winemaker, the role of yeast in wine production is to digest sugar and produce alcohol, which remains in the wine, and carbon dioxide, which is released as gas. Each species of yeast has its own signature in how it transforms grape flavors through metabolism. “If Manet, Rembrandt, and Warhol were each to paint a portrait of Halle Berry, each would be a representation of her—but each with its own visual impact,” Carpenter says. In effect, that’s what different yeast strains do, but with flavor. Winemakers just want to make the best wine possible, and in our technology-driven age, it’s amazing that the presence of a million-plus year old single-celled microorganism can make all the difference.