North Coast vintners hope for warmer days accelerate this year’s later harvest

Wine grape growers at the north end of the North Coast region this time of year typically are fretting whether they’ll be able to wrap harvest before late fall rains begin in earnest.

But an unusual flip-flop in weather this season has seen a sizable proportion of the fruit off the northern vines, while picking has barely started in the south. This is pushing harvest for the region’s billion-dollar crop deeper into fall and closer to the time when rains typically begin in earnest and the season is effectively over.

“We normally see harvest start in Sonoma and Napa (counties) and then finish in Lake and Mendocino (counties), being more north,” said Christian Klier, North Coast wine grape broker for Novato-based Turrentine Brokerage. “So I have to say this is the first time in my 25-year career I've seen this happen.”

This season started roughly three weeks later in Sonoma and Napa counties than in the 2020-2022 drought, thanks to above-normal winter rains and cool spring weather. The first new vine growth emerged in Mendocino and Lake counties later than in the south.

And that lag in the season has continued for much of Napa and Sonoma counties, with cooler mornings through the summer and into fall, while Lake and Mendocino counties largely remained on track. Then came cooler days in mid-August as the northern edges of the tropical storm remnant of Hurricane Hilary passed through the region.

“In the overall, we didn’t have the early morning fog that others had like in Sonoma and parts of Napa,” said Bill Pauli, an owner of Yokayo Wine Co. in Ukiah. “We did not have heat spikes like last year, when we had 110- to 115-degree (Fahrenheit) days, which shut everything down.”

Grape vines are in their sweet spot for photosynthesis generally between 77 and 95 degrees Fahrenheit (25-35 degrees Celsius), according to a 2020 paper in the online journal Plants. So when the temperature in the vineyard climbs above 95 degrees, and certainly over 104 degrees (40 degrees C), or drops below 50 degrees (10 degrees C), the vines turn down its processes, similar to how it protects itself from drought, according to the Greek researchers.

So with the cooler North Coast season this year, harvest for sparkling wines, which typically call for grapes to be picked at lower sugar levels than for table wine, also came about three weeks later than in the past few years, kicking off in late August.

As of the end of September, picking of early-ripening grape varieties sauvignon blanc, chardonnay and pinot noir in Lake and Mendocino counties was about 85% done, Klier said. And harvest of red varieties there is over one-third completed, including the expanding crop of cabernet sauvignon in southeastern Lake’s Red Hill appellation.

Meanwhile, less than 10% of sauvignon blanc and chardonnay in Sonoma and Napa counties have been picked, only about 5% of pinot noir and around 2% of cabernet sauvignon and other red grapes, Klier said. Warmer regions of the two counties – Sonoma County’s Alexander Valley and north of Yountville in Napa Valley – were trending closer to their average timing for harvest, he said.

At Ram’s Gate Winery in Sonoma Valley, winemaker and General Manager Joe Nielsen was eyeing optimistically the weather forecast through the first week of October.

“We’re seeing mid-80s and some high 80s in the 10-day forecast, so we could go from 10% (complete) to 50% in matter of days,” Nielsen said. “It’s going to be a very busy beginning of October.”

The 10,000-case-a-year winery was almost 70% done with harvest at this point last year, and even in the pre-drought 2018 and 2019 seasons the pinot noir and chardonnay grapes were already in the tanks and picking of red grapes had begun. The vintner sources one-third of its fruit from the estate vineyards and the remainder from long-term contracts at vineyards around Sonoma County and at Hyde Vineyard in Napa County.

Nielsen’s records show this season is tracking similarly to 2010, which also was a cool season before a warm September brought the vintage in for a notable finish. The following year, however, with its late year and rain-soaked October, early finish isn’t one Nielsen or other North Coast winemakers want to remember.

“We could go from concerned about the vintage to a classic California vintage, where we have great concentration (of flavors and colors) and at reasonable alcohols,” Nielsen said.

A concern among North Coast growers in the past two decades has been certain styles of winemaking that call for grapes to remain on the vine longer -- colloquially known as “hang time” – to high intense flavor, color and other characteristics. But that may result in higher sugar levels in the grapes and higher-alcohol wines.

Aimee Baker, director of luxury winemaking for St. Helena-based Trinchero Family Estates, has seen all the planned sauvignon blanc come in from Napa Valley, along with some pinot noir from Sonoma Valley, Sonoma County’s Green Valley and Mendocino County’s Anderson Valley. Some chardonnay has arrived from Sonoma Valley and Russian River Valley, but that white grape variety is lagging at the vintner’s sources in southern Napa County.

Picking of the first cabernet sauvignon for the seven luxury brands Baker oversees were set to begin the first week of October from Napa Valley’s Oakville, Rutherford and Coombsville appellations.

“It’s kind of a surprise that we had a cool summer, but there was enough heat for photosynthesis,” Baker said. “We test and sample once a week, so we realized that we were tasting and measuring development that was further along. The vines are very balanced with not a lot of extra fruit, and they seem to be running on their own internal clocks.”

Baker estimates that picking for her brands will continue into November, with hillside vineyards trailing. But for Trinchero’s mass-market brands such as Sutter Home that source fruit from other areas of California, there remains a lot of harvest left this year, Baker said.

Jeff Quackenbush covers wine, construction and real estate. Reach him at jquackenbush@busjrnl.com or 707-521-4256.