People talk about a wine having heat. But smoke? That’s another matter entirely.
For vintners in California, it’s a growing concern. The changing climate has not only increased the number of wildfires that ignite each year, it’s also increased the length of wildfire season — in some years by as much as three months.
And when they do rage, wildfires belch massive amounts of smoke into the atmosphere, shrouding the sky and surrounding landscape in thick, noxious hazes. One problem for vintners is when their grape clusters sit in this haze for extended periods of time. In fact, it can be catastrophic.
Following the destructive 2020 fire season in California, growers and vintners reported about $600 million worth of grapes were lost to actual or perceived smoke damage. Some wineries, including Opus One in Oakville, abandoned their 2020 vintage because of so-called smoke taint, and instead re-released wines from their 2018 and 2019 stocks. It’s a tough decision for any winemaker, but it makes sense. Smoke taint causes wines to have unpleasant characteristics — like someone dumped a cigarette ashtray into your glass.
For this reason, the wine industry and the federal government have teamed up to research the detection of smoke taint and ways to mitigate its impact.
“Research ticked up along with concerns from the wine industry.”
Arran Rumbaugh is a research chemist with the US Department of Agriculture’s Agricultural Research Service. She earned her doctorate in agricultural and environmental chemistry from the University of California, Davis in 2021, and was hired by the federal agency in August 2022 to work specifically on the issue of smoke taint.
“There has been a need for this,” Rumbaugh said. “In the US, research interest began in 2017, but 2020 was the massive smoke-event year. Research ticked up along with concerns from the wine industry.”
There’s still much to learn about the overall impact of smoke in vineyards, but with prolonged exposure, compounds in the smoke are absorbed through a grape’s skin and into the berry. Once there, sugars in the berries bond with the compounds. When that happens, the situation can become tricky for vintners.
“The compounds change from something you can smell to something that you can’t as the sugar changes the property of the compound,” Rumbaugh said.
Once that happens, it becomes harder for a vintner to quickly assess the quality of their grapes. And when they lack that knowledge, they can more easily make the mistake of spending time, money, and energy harvesting grapes that, in the end, will create sub-optimal wines with negative tastes and aromas.
“I’ve tasted one, I believe in 2020,” Rumbaugh said. “It was the most impacted wine of that season and it’s really interesting how it’s not just the taste of burnt wood. It has this ashy aftertaste that’s similar to cigarettes.”
It remains unclear to researchers whether hybrid grape varieties would perform much better in the presence of such smoke. Data in research literature has shown there are different levels in incident based on grape variety, but whether that is attributable to the skin thickness is still unknown.
Much of Rumbaugh’s research is about identifying the point at which a grape’s exposure to smoke crosses a threshold that makes it unusable for wine. More than that, her work is contributing to a broader effort to develop fast-acting tools vintners can use to measure the smoke-derived compounds of their grapes from their vineyards. These tools under development can cut the time of determining a grape’s quality from weeks to days, or even hours.
Such tools would make a huge difference to people such as Duff Bevill, who’s been working vineyards across Sonoma County since 1973. When wildfires break, speed is of the essence. Bevill said proactive measures would be useful, something like spraying a thin layer of protective clay on vines.
“But even if I knew something like that were available, I couldn’t get it on all the fields in a reasonable amount of time,” he added.
Ultimately, it’s information about grape quality that he needs.
“The value to me as a grower is knowing that the winery will still take the grapes,” he said.
Congressional leaders have sought to pass legislation that would dedicate millions of dollars into research around improving methods to screen for smoke-impacted wines, as well as into developing tools to mitigate or eliminate the taint from wine altogether. Most recently, California’s Sen. Alex Padilla and Rep. Mike Thompson in June 2023 submitted twin bills in Congress calling for $32.5 million total to be allocated across 2024 through 2028 for such research. The bills have little chance of being enacted, but are the latest in repeated attempts by the lawmakers to address the issue.
There is at least one silver lining, which is that grapes impacted by smoke taint aren’t entirely unusable. In some cases, they can be a blessing in the production of non-wine spirits. Leslie Merinoff, the founder of Matchbook Distilling Co. in Greenport, NY, discovered as much.
“I just had a feeling that if you distilled smoke taint wine, you’d have flawless brandy,” Merinoff said.
And that’s exactly what she did.
Once the 2020 wildfire smokes cleared from vineyards in Oregon, she worked with two to procure red and white wines impacted with smoke taint. Both turned out to perfect for making be premium brandies. You can read more about that here.