Under a hazy blue sky, Aimee Sunseri strolls briskly through her family’s vineyard 1,000 feet above the east edge of Napa Valley.
Dense and heavy clusters of dark grapes bracket her as she marches up a gentle slope, ducks through trellis wires to get a few rows over, then reverses her direction. She repeats these round trips a dozen times, through blocks of merlot, cabernet sauvignon and petite sirah.
She zigs and zags, stopping every 15 feet or so to pluck a single berry from a cluster, then drops it gently into a Ziploc bag. She will have gathered around 300 grapes by the time she is finished an hour later.
Then she will hand them off to a courier who will deliver them to ETS Laboratories in St. Helena, where technicians will analyze the fruit for residue from the wildland fires that swept across Napa, Sonoma, Mendocino and other north state wine enclaves starting Sunday night, Oct. 8.
Scientists continue to study how smoke affects maturing wine grapes, but at its worst it mars finished wines with a smell and flavor akin to smoldering cigar butts in an ashtray. While winemakers often welcome a whiff of smoke in their wines – thus the use of pricey French barrels with heavily toasted staves to age wines – they don’t want so much that the fruit of the wine is obscured.
“It’s far, far too early to speculate about the potential impact of smoke on grapes and wine,” says Gordon Burns, technical director of ETS Laboratories, where some 30 chemists, microbiologists and other technicians are analyzing samples for smoke and other winemaking issues.
For one, he notes, the October fires came late in the growing season, and the fruit may not have been as susceptible to the kinds of smoke damage that growers and winemakers saw when fires spread through Mendocino, Trinity and Humboldt counties relatively early in the growth cycle in 2008. (Despite distracting smoke taint in wines at that time, at least one enterprising vintner took advantage of the setback to release an unabashedly smoky novelty wine, for which he found a surprisingly receptive audience. That raises the possibility that history could repeat itself this vintage.)
During her focused meandering, meanwhile, Sunseri occasionally pauses to nibble a grape. “I’m not picking up any smoke, but I’m aware that that could change,” she says.
Overall, the smoke that may tarnish some north state wines from the 2017 vintage is of relatively small concern to vintners. For one, an estimated 75 percent to 90 percent of the crop had been picked before the firestorms.
More to the point, vintners are mindful that many of their neighbors sustained more grievous losses. The fires killed 43 persons, destroyed an estimated 5,700 structures, displaced thousands of residents and seared almost a quarter of a million acres.
By comparison, of the approximate 1,200 wineries scattered about the hills of Napa, Sonoma and Mendocino counties, fewer than 10 were destroyed or extensively damaged, reports the trade group Wine Institute. Few vines were consumed, and several that were scorched and look weak now may revive next spring when the growing cycle resumes. (If any of Napa County’s 45,000 acres of wine grapes need to be replanted because of fire damage, the cost will be about $200,000 an acre, which includes three years of lost production while new vines mature to commercially viable production, calculates Greg Clark, the county’s agricultural commissioner.)
About 20 miles from the Sunseri vineyard, along Silverado Trail on the floor of Napa Valley, Ernie Weir snaps a blackened and blistered cane on one of the vines touched by flames at his winery Hagafen Cellars, the valley’s only kosher winery.
“Look, it’s still green inside,” he notes. “It’s like they’ve gone into early dormancy. I’m not sure they are dead.”
A few feet from the vineyard lies the crumpled and charred ruins of a guest house. Behind him squats the hulking black remains of a two-year-old Kubota tractor, one of several pieces of equipment he lost to the fire. He also lost a chicken coop, and 19 of his 20 hens; the lone survivor has been relocated.
On the concrete crush pad at the back of his nearby winery, two workers chip painstakingly at the solidified remains of plastic grape bins that had melted and flowed into a drain.
Also behind the winery tower a half-dozen stainless-steel fermentation tanks holding about 14,000 gallons of cabernet sauvignon, cabernet franc, merlot and syrah. Weir points out charred insulation and warped plastic on and about the tanks. How the encroaching heat of the fire may have affected the wine in the tanks remains to be known. Like cases of wine in the holds of a ship moored too long in a hot port, the wine’s color could have faded, its aroma could be stunted and its flavor could show signs of oxidation, but Weir’s lots have yet to be analyzed for damage.
Weir is a picture of sanguine gratitude as he strolls about the winery. As he passes blackened cypress trees, a scorched arbor connecting winery and tasting room and a pile of ash that before Oct. 8 was a wine barrel, he also points to a healthy tree sagging with bright and plump Persian limes, unaffected by flames. And not far beyond the lime tree is a stand of olive trees whose similarly untouched fruit he is about to harvest.
“Every day is another step forward. Today is better than yesterday,” Weir says. The fire, he adds, left him with two lessons. One is to continue to build with non-combustible materials. Despite the proximity and fierceness of flames, his winery (corrugated aluminum) and his tasting room (stone) escaped relatively unblemished.
The other is that despite high winds that fanned the flames, the area’s vineyards formed fairly effective firebreaks. “Vineyards saved the day,” Weir says. “In many cases the fires burned up to the edge of vineyards and stopped. Vines were green and lush, still holding moisture. They weren’t as flammable as dry grass and trees.” Throughout the area, vineyards stand out in bright autumnal hues against hillsides that are studies in black and white.
Weir and other members of Napa Valley’s robust wine trade fret that tourists will forget its celebrated restaurants, tasting rooms and posh boutiques for fear that the enclave has been transformed into a vast wasteland. “The worst thing will be if we are abandoned – the lost jobs, the economic recession that could result,” Weir says. (Tourism in Napa Valley employs some 13,000 persons, according to the trade group Visit Napa Valley, which is maintaining a website for updates on the status of businesses – www.visitnapavalley.com/emergency.)
Throughout the valley, business is slowly rebounding. Florists inside the valley’s highest profile restaurant, The French Laundry in Yountville, were arranging bouquets for that night’s reopening. At nearby Bouchon Bakery the pastry cases were as brightly and as temptingly stocked as ever, though the customary line of customers out front had yet to materialize.
As smoke slowly yielded to sunshine, specks of ash drifted onto a lemon tart and cup of coffee on the bakery’s patio, but a passing convertible had its top down, and cyclists weren’t wearing respirator masks.
Aimee Sunseri, meanwhile, was preparing to resume the crushing of this year’s grapes. While most other vintners had concluded the harvest, she still had a third to a half of her crop hanging.
As flames neared her family’s Nichelini Family Winery early in the fires, her father rounded up six large trucks, loaded them with processing equipment, barrels and even wines from the tasting room and vacated the premises. Now they were being returned and primed to finish the harvest and to reopen the tasting room.
She is eager to resume picking and pressing. She pulls from a pocket a refractometer, a tool to measure sugar in unfermented grape juice, a gauge for deciding when to pick. She spreads a few drops of petite-sirah juice on the refractometer’s plate, peers into the instrument’s eyepiece, and pronounces the sugar content at 25.1 Brix, the sweet spot to start harvesting.
If the tests for smoke taint come back positive, she isn’t sure what she will do with the wine. Winemakers have several options, however, to salvage tainted wines, notes Anita Oberholster, cooperative extension specialist in enology at UC Davis. During the early stages of winemaking, they could reduce contact between grape juice and grape skins, where smoke residue congregates. They could use strains of yeast that amplify the fruit character of wine, thus masking smoke. They could blend tainted wines with untainted. They could forgo the aging of wine in heavily toasted oak barrels.
For Sunseri, who also is the winemaker for New Clairvaux Vineyard at Vina in Tehama County, this is her first vintage in which she may have to cope with smoke taint. If any adjustment to her wine is necessary, she is leaning toward reverse osmosis, an involved high-tech process that involves filtering wine to screen out smoke-related compounds, but Sunseri is uncertain about the method for fear it might strip the wine of positive attributes.
“I don’t want to compromise the (color, aroma and flavor of) the wine,” she remarks as she reflects on her potential predicament. “I’m going to pray for the best.”
Wine critic and competition judge Mike Dunne’s selections are based solely on open and blind tastings, judging at competitions, and visits to wine regions. He can be reached at email@example.com.