When the wildfires in October of 2017 hit, the grapes at St. Helena's Quintessa were left largely unaffected; already harvested and on their merry way to becoming wine.

But when the smoke and fire came earlier than expected last year in 2020, there wasn’t much winemaker Rebekah Wineburg thought she could do about it.

“From the first moment, I decided we were going to do a complete harvest, but I didn’t know what we could do about the smoke,” she said. “We don’t really know what the effects of smoke are, but it's a challenge … To me it’s a marriage; you stick through it, you want to learn from it, and that was our philosophy in 2020.”

One of Wineburg’s colleagues — Ken Bernards of Ancien Wines — had been trying out an ozone treatment container for his own grapes, and back in 2017, had treated his smoke-impacted harvest as a sort of experiment. Fast forward three years and Wineburg decided she also wanted in on the trial.

In partnering with Purfresh's wine division, Quintessa leased its own container to treat its grapes through the specialized 24-hour ozonation process. This process is supposed to oxidize unwanted entities like bacteria, mold, E. coli, salmonella and viruses, and according to Purfresh CEO Christian DeBlasio, it may help mitigate the impacts of smoke taint as well.

“In looking at the structures of different chemicals that we've mitigated before, we realized smoke taint molecules had a lot of similar properties,” said DeBlasio, “And by treating grapes before crushing them, you could remove a lot of the long term damage that smoke taint does in the end wine product down the road.”

Wineburg, whose education background is in chemistry, looked over the studies done on this type of controlled ozone (O3) treatment to mitigate smoke taint and decided it didn’t go against her principles of natural, organic farming. During 2020’s harvest season, she started by taking and treating samples of the grapes to see if there was a noticeable difference later in the winemaking process.

“I wasn’t necessarily sure that it was going to work, so I set up two complete trials where I made wine that was treated and wine that wasn’t treated,” she said. “And then, post-Glass Fire, I treated everything.”

Both Wineburg and DeBlasio say that Purfresh is unique in that it cools and primes grapes for wine, undoubtedly due to the company’s history with engineering-controlled storage containers for produce traveling across the ocean. While we won’t know for sure how the Purfresh treatment will impact Quintessa and the other participating wineries’ products until they are ready for consumers, Wineburg did say that from what she is seeing so far, the treated wines seem a bit fruitier.

“It’s not a silver bullet, but if we have another smoke event, I will surely do this again,” she said. “From what I am tasting in the cellar, there's some blocks that seem affected by smoke, some don’t, and it is not as logical as when you picked, so that tells me that there’s still a lot more to figure out.”

Wineburg is among the group of winemakers passionate about researching smoke taint and its impacts on grapes and is lucky enough to have partnered with Anita Oberholster from UC Davis to study some of their frozen 2020 vintage.

“I want to continue research because I think that there's so much that we need to learn about smoke,” said Wineburg. “If people just don’t make wine when there’s a smoke event … This becomes an existential problem.”

Purfresh acknowledges this scrambling of wineries and vineyards surrounding wildfire season, but is working to ensure its technologies improve the product across the board, smoke taint or not. Farmers and winemakers can use these containers for storage and preservation purposes, or even to help remove field-applied sulfur dioxide prior to crush.

“We're not a business that's going to survive running around the world after a certain wine region has wildfire and smoking,” said DeBlasio. “We've got other solutions, and we feel that our products add benefit in the long-term winemaking process.”

For example, DeBlasio explains that while undergoing ozone treatment, the grapes also experience an increase in anthocyanins, tannins and stilbenes. “And those are the characteristics that a lot of people love to have in wine, especially high in red wines,” he said.

As it pertains to the issue of smoke taint, though, DeBlasio concurs with Wineburg that ozone containers and Purfresh technologies are not an end-all, be-all.

“I would be remiss, if we didn't let the industry know that there are situations that are not fixable,” he said. “And what's important, too, is understanding the certain limits and levels and expectations of what can be fixed to where it's not noticeable.”

Wineburg and the Quintessa estate will continue to use the Purfresh container during harvest for treatment research — in addition to loaning it for use by other smaller wineries — as well as looking into other means of reducing smoke taint in wine.

As long as there are wildfires, there will be smoke, and Wineburg thinks a multi-pronged approach will probably be necessary to preserve the quality of wines coming from the region.

“Last year’s fire started so early that you had nothing else to do … but Quintessa is an estate winery, and our philosophy is that our wine is an expression of the estate,” she said. “We are committed, we are stewards, we’re organic and biodynamic farmers … and mostly, we have a deep connection to our land.”

You can reach Sam Jones at 707-256-2221 and sjones@napanews.com