As most of you know, Napa is on fire. Again. And those in the “know” in regards to wine are busy postulating on the effects of smoke taint as it relates to “veraison.” Is smoke taint becoming a thing with wine? Too early to tell and certainly interesting speculation for wine conversation.
Meanwhile, what is the meaning of the cryptic term “veraison?” Veraison is defined this way: “In viticulture (grape-growing), veraison is the onset of ripening. The term is originally French (véraison / veʀɛzɔ̃), but has been adopted into English use.” (Wikipedia). Veraison has everything to do with the permeability of the grape skin. Less ripened grapes have thicker skins, which suggests they are less susceptible to smoke taint. That’s where we are right now, in the early part of the grape ripening season, so most likely smoke taint will not be a factor for the current fire.
Here’s more about the current fire affecting Napa County, courtesy of W. Blake Gray | Posted Tuesday, 03-Jul-2018:
A huge wildfire has crossed over into Napa County, less than a year after the region was devastated by one of the worst fire outbreaks in northern California history.
The air was brown in San Francisco, about 60 miles south of Napa County, on Sunday morning from smoke from two Wine Country fires: the County Fire, which started in Yolo County east of Napa, and the Pawnee Fire in Lake County north of Napa.
The County Fire is growing like Godzilla: 60,000 acres as of Monday evening, with only 5 percent contained. It is already larger than the Tubbs Fire that last year devastated northern Napa Valley and neighboring Sonoma County, and it is growing at a faster rate – 33 percent on Monday alone. Cal Fire believes it started in dry vegetation; the cause is under investigation.
However, some of the news on the County Fire is so far, so good (cross fingers). CalFire says it threatens 700 structures – six times as many as 12 hours earlier – but so far has not destroyed any. At this point, no wineries are believed threatened, and we learned last year that vineyards are effective natural firebreaks.
“I’ve looked at the map many times here. It’s not anywhere in our grapegrowing vicinity,” Heidi Soldinger, marketing and communications manager for Napa Valley Grapegrowers, told Wine-Searcher. “At this time, we’re feeling like we’re pretty safe. But after what we experienced in October, I’m not going to make any predictions.”
For wineries, smoke taint is almost as big a concern as the fire itself. California wineries have had great interest in smoke taint research since last year’s wildfires.
Napa’s grapes have not yet gone through the process of veraison, where white grapes turn black, so they are less vulnerable to smoke taint than they will be soon. But that doesn’t exempt them from risk. In 2008, Anderson Valley Pinot Noir grapes were heavily smoke tainted by fires that occurred pre-veraison in June.
“We do not currently know exactly how much fresh smoke is needed for a real risk of smoke taint development in the wine,” Anita Oberholster, assistant cooperative extension specialist for UC Davis Department of Viticulture and Enology, told Wine-Searcher. “However, we do know that pre-veraison it will take more fresh smoke and longer exposure times for smoke taint risk compared to post-veraison grapes. The less ripe the grapes, the smaller the risk. Green hard berries have low risk whereas larger, softer, green berries have medium risk, with post-veraison grapes having the highest risk.”
Fortunately, though the County Fire has leapt into Napa County, it is still north and east of Napa Valley, and the wind in Napa County tends to blow from the ocean (west) to east. Winds can change, and fires can leap, but for now it’s a worry for wineries more than a threat.
To the north of Napa, however, the Pawnee Fire has already destroyed 22 structures in Lake County. It’s only one-third the size of the County Fire, and it was 75 percent contained as of Monday morning. The cause of this fire is also under investigation.
It’s possible this fire might have more impact on 2018 Napa Cabernets than the County Fire, because much of the Cabernet Sauvignon grown in Lake County finds its way into Napa Valley bottlings. A wine labeled as “Napa Valley”, or any other AVA, must contain at least 85 percent grapes from that AVA. Lake County Cabernet grapes fetched an average of $2500 per ton last year; for Napa County Cabernet, the average was $7500 per ton. It’s also possible that the great majority of Lake County grapes won’t be affected at all.
California usually has dry summers – that’s why the wine is so good – and is thus vulnerable to fires. This season they seem to be early. The state had below-average rainfall again last winter after a rainy winter in 2016-17 ended a five-year drought. But rain might not matter: in 2017, after that wet winter, more than 500,000 acres burned in California, more than double the destruction of dry 2016.
Wednesday July 4 is the biggest fireworks day of the year in the US. Not, however, after last year in wine country.
“In Napa County we’re not having any fireworks this year,” Soldinger said. “Everyone is very aware. Our thoughts go out to everyone in Yolo and Lake County. We know how that feels.”