Microbes already growing on grape plants may help neutralize one of the compounds responsible for wildfire-exposed grapes’ off-putting flavors, new research suggests

Sarah Kuta - Daily Correspondent

October 2, 2025 5:20 p.m.

Smoke from wildfires can cause off-putting, ashy flavors in wine. Pexels When wildfires sweep across the landscape, they often leave charred forests, grasslands and man-made structures in their wake. But for winemakers, flames aren’t usually the biggest source of worry—it’s the smoke, which can blanket vineyards and impart an unpleasant, ashy flavor on the resulting wines.

In places like California, Oregon, Washington and Australia—all home to robust wine industries and susceptible to wildfires—smoke taint is becoming a major issue. In 2020 alone, American wine industry representatives estimate that smoke taint from California’s record-setting wildfires caused $3.7 billion in losses. Climate change, which is intensifying and lengthening wildfire seasons, is poised to make the problem even worse.

Now, researchers say they may have discovered a way to preserve smoke-tainted wine. Bacteria found growing on grape plants may help neutralize one of the compounds responsible for the off-putting flavors, they reported October 1 in the journal PLOS One.

Fun fact: Red, Red Wine

Pigments called anthocyanins give cabernet sauvignon, one of California’s most popular wines, its color.

In experiments, researchers identified two strains of the bacterium Gordonia alkanivorans capable of breaking down guaiacol, one of the main compounds that give wildfire-tainted wine its unwelcome, smoky essence. They also discovered the genes within the bacteria that give them their guaiacol-degrading superpowers.

For the study, scientists gathered leaves from cabernet sauvignon and chardonnay grape plants grown in a California greenhouse. Vintners don’t intentionally use leaves to make wine, but they’re sometimes accidentally harvested alongside the grapes. Leaves also provide a large surface area for wildfire smoke to penetrate.

“When you have a smoke exposure, most of the smoke is actually going to impact the leaves rather than the fruit,” study co-author Thomas Collins, an agricultural chemist at Washington State University’s Wine Science Center, tells the Scientist’s Andrea Lius. “And there’s some evidence that some of these compounds can translocate from the leaves to the fruits.”

The two strains of Gordonia alkanivorans grew into bright orange colonies while degrading guaiacol. Claudia Castro Researchers grew eight bacterial colonies from the bacteria found on the leaves, then exposed them all to a guaiacol solution. In the end, only two strains of G. alkanivorans were able to grow in the guaiacol, forming bright orange colonies in the researchers’ petri dishes. The other bacteria died.

Additional testing with the G. alkanivorans strains revealed that, after 72 to 96 hours, the bacteria had almost completely wiped out the guaiacol. Meanwhile, the bacteria continued to grow and proliferate, which suggests they’re able to use guaiacol as a food source.

But guaiacol is just one of volatile compounds known to cause smoke taint. Experiments with different volatile compounds didn’t show bacterial growth, suggesting the two G. alkanivorans strains might be guaiacol specialists of sorts. That was a bit of a surprise to the team. “There’s still room to evaluate why they’re so selective,” Collins tells the Scientist.

Based on this finding, researchers will probably need to identify additional bacterial strains if they hope to address other culprits beyond guaiacol. Another possible challenge to overcome: G. alkanivorans appears to be relatively rare. After researchers created a wildfire-like “simulated smoke event” in a field full of merlot vines, they couldn’t find any G. alkanivorans on the plants—a puzzling mystery, given the bacteria’s propensity for gobbling up guaiacol.

Still, the scientists are heartened by their results. In the future, winemakers might be able to take advantage of these naturally occurring, beneficial bacteria to address or even eliminate smoke taint in wine. For instance, vintners may be able to prevent the guaiacol from getting into the grapes in the first place by inoculating vineyards with the microbes, per Science’s Celina Zhao. Or perhaps researchers could banish guaiacol by incorporating the bacteria into the fermentation process.

These types of proactive strategies might even end up being more effective than existing smoke-taint mitigation techniques, such as filtering wine through activated charcoal. Though such processes remove the smoky notes, they also tend to strip the wine of more desirable elements, like its vibrant color and subtle flavors.

“This microbial approach has the potential to be a little bit more specific without impacting the overall quality of the wine,” says Cole Cerrato, a food scientist at Oregon State University who was not involved with the research, to ScienceNews’ Carly Kay.

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