Wine News Smoke and Mirrors: Fixing a Fiery Vintage

Smoke and Mirrors: Fixing a Fiery Vintage

Smoke taint is a clear and present danger on the West Coast.
© ETS | Smoke taint is a clear and present danger on the West Coast.
Smoke taint is the story of the 2020 vintage, so how can winemakers work around it?
By W. Blake Gray | Posted Sunday, 20-Sep-2020

Maybe this is good news: current research shows that in red wines, smoke taint is least noticeable in a type of wine that California not only is particularly well-suited to make, but already makes by the boatload.

High-alcohol, high-pH red wines with residual sugar are the best at masking the compounds of smoke taint, according to a seminar for winemakers held this week by UC Davis.

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Dozens of winery representatives attended the online "office hours" Tuesday of UC Davis professors Anita Oberholster and David Block, and no wonder, with smoke blanketing most of the West Coast. Like it or not – winery principals most assuredly do not – potential smoke taint is the story of the 2020 vintage.

The biggest takeaway was about the style of wines. For red wine grapes, producers have two very different choices. They can try to make a rosé, a light red wine, or even a white wine, like a white Pinot Noir, because those wines have far less skin contact and are less likely to show smoke taint.

"There's a chance, I personally think, that you can make a pretty good wine" by making a lighter red wine from red grapes with little skin contact, Oberholster said. "You just need to be careful. With light skin contact you'll get 10 to 20 percent of what you taste in a microferment."

Or they can go full-on 2003 Napa Valley: high alcohol, low acid, slightly sweet.

The reason has less to do with the drink and more to do with the drinker, Oberholster said. About 25 percent of people cannot detect smoke taint in wine. The other 75 percent have enzymes in their saliva that release bound compounds from inside the wine, so that even if the wine doesn't smell smoky, it tastes like dating a smoker.

"At low pacid, the enzymes in your saliva are not as good at hydrolyzing," Oberholster said. "It's a tasting effect. The higher the alcohol, the less it hydrolizes. If you have a little bit of residual sugar, a little bit higher alcohol, a little bit less acid, you can't taste it."

But wait, there's more good news for people who like these kinds of wines anyway: winemakers of late-harvested grapes like Cabernet Sauvignon may not be rewarded this year for picking their grapes early. Red wine grapes harvested early tend to have a green character, described favorably as a characteristic herb note and unfavorably as green vegetables. Early harvested red wines also tend not to be as fruit-driven. Both of these are bad if the grapes are harboring the compounds that cause smoke taint.

"The amount of phenolics affects it," Oberholster said. "Any green character enhances it. Fruit suppresses it."

There's something in the air

Unfortunately, the news for Oregon isn't as good as for California, as should already be apparent. 

"Pinot Noir is delicate so it's easier for smoke characteristics to stand out," Oberholster said. But Syrah is even more vulnerable to smoke taint than Pinot because Syrah naturally has more of the compounds that cause smoke taint, which is why some Syrahs in good years taste a little smoky.

As for white wines, the expensive ones will be safer than the cheap ones.

"For white grapes, machine harvesting does have an impact," Oberholster said. "These compounds are mostly in the skins. If you do very little skin contact, very quick pressing under mild pressure, you can still have a juice that doesn't have much impact. Machine harvesting damages the skins, so there is additional risk. Also, the grapes tend to start fermenting on the way back to the winery, so you get more skin contact than is ideal."

As to how much of the West Coast harvest will be affected, Oberholster just doesn't know. She said that smoke taint isn't necessarily related to air quality, especially to the publicly available AQI numbers that have been so alarming in the past week.

"AQI levels are based on 2.5 PM particles," Oberholster said. "We've found that smoke taint does not have a big relationship to that number. Smoke taint is more caused by 1.0 PM, much smaller particles."

Also, and this is encouraging news for all the grapegrowers who saw smoke slowly drift over their vineyards, older smoke is not as dangerous as smoke less than 24 hours old.

"The older the smoke gets, the less the correlation there is between AQI and potential smoke taint," Oberholster said. "Carbon in smoke is very stable. Volatile phenols are not stable. They can break down. It depends on wind direction. We've had vineyards very close to the fire being much less affected than vineyards many miles away."

Because smoke taint research is still in its early stages, Oberholster asked wineries and grapegrowers to freeze samples from their grapes and the microfermentations they must do to qualify for crop insurance. She hopes to build a large database from 2020 so she can compare it to atmospheric data to study where smoke taint appears and where it does not.

She also said that growers should keep frozen samples in case they later need them to try to file a claim on their crop insurance if the grapes are rejected by a winery.

"Crop insurance said if you can show chain of custody, they will evaluate all the relevant information," Oberholster said. "We're suggesting freeze grapes, freeze wine, in case you have to go back to them. These things are very stable in the freezer."

One thing that has changed recently in advice for growers is regarding ash. Oberholster said she has learned ash on grapes can put out volatile phenols for a week, so when possible, growers should wash the ash off of their grapes. A number of companies are selling airblast cleaners but she said they are not as effective as water.

UC Davis and the Australian Wine Research Institute are both studying compounds that could be sprayed on grapes beforehand to prevent smoke taint from entering the grapes. Some companies are also selling compounds like this but there is no research yet into their effectiveness.

Finally, this is your periodic reminder that while some vineyards will be tainted enough so that the grapes will not be harvested, other vineyards will be completely unaffected and should be able to make wines just as they usually do. There should be a 2020 vintage of some kind – assuming the Earth doesn't crack open and swallow us up first. Which, you never know, because it's 2020.

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