Local winemaker Alisa Jacobson and I reconnected April 2 on a “gorgeous” spring day — one where it’s “easy to forget that climate change isn’t going to go away,” she said.
Jacobson, winemaker/owner of Turning Tide Wines and a partner on other wine labels, moderated the “Winemaking in Today’s Climate Conditions” at this year’s Unified Wine & Grape Symposium in Sacramento in January.
She is the co-chairperson of program development for the annual symposium as well as co-chair of research on California’s Smoke Exposure Task Force.
The conditions in question run the gamut from relentless heat (Labor Day 2022) to wildfires, common throughout the West Coast, to extreme freeze conditions, according to Ben-Min Chang, research scientist for Agriculture and Agri-Food Canada, and one of the four panelists at the January seminar.
Just 11 days before the symposium, Chang noted, British Columbia had suffered a “really bad” freeze that saw sustained temperatures below 28 degrees Celsius. Vines can only survive temperatures that cold for six hours, he said.
Freezing and intracellular ice formation cause cell death in a vine’s trunk and canes. If enough cells die, the affected portion of the vine dies.
Washington State University’s Tom Collins, longtime assistant professor of viticulture and enology, called both smoke and freeze issues “intriguing” to North America’s wine industry.
Grapes suffering from smoke taint present a smoky, “cigar butt” aroma and flavor, and the smoke notes linger as the wine ages in a tank or barrel, he said; on the flip side, “low-level” smoke exposure might not harm grapes.
Stations to monitor air quality during fires are common in vineyards throughout the West Coast — especially as a fire in one state may damage grapes in another. Washington State University collects data from eight states, Collins told attendees. With grants, “we’re building a network of sensors in commercial vineyards.”
In early October 2019, freezing temperatures hit eastern Washington when “most of the cabernet sauvignon was still on the vines. We lost lots of fruit,” Collins said. Then came high winds, and the shoots’ leaves turned “crispy” and fell apart.
Pieces of those leaves then got stuck in grape clusters headed for processing during harvest.
“Leaves in grapes created an herbaceous flavor not unlike herbal tea,” he said.
The “frequency and intensity” of extreme weather are increasing, said panelist PJ Alviso from Duckhorn Wine Co. He urged growers and winemakers to “be realistic and involved and to stay ahead of the curve, as the traditional (fixed) strategies will likely fail nowadays.”
Weather remains unpredictable, he said, noting that the 2022 growth season was “a great year — until Sept. 5 (the Labor Day heat episode).”
Panelist Elisabeth Forrestel of the University of California, Davis, emphasized that winemakers might “reconsider” the meaning of phenolic ripeness — when grapes’ skins and vines’ stems mature from bitter to softer and rounder — and focus on “shortening our growing seasons” so that grapes get harvested before the risk of wildfire smoke taint and frost episodes increase come October and November.
Back to this month, when Jacobson and I sat outside on a warm spring morning.
She views the overall Santa Ynez Valley as a “less risky” growing region because of Santa Barbara County’s proximity to the ocean’s cooling influence. In contrast, Paso Robles, located farther inland, faces more “extreme cold and heat.” Like Collins in Washington, Jacobson has handled Paso Robles’ clusters of cabernet sauvignon full of frosted leaves that leave a noticeable aroma of “lemon Pine Sol” in the juice.
A solution, of course, is to filter the wine with a membrane. However, filtering can eliminate good flavors along with bad, often “stripping” the wine, she said. Think of it as “throwing good money after bad wine” — wine that might best be suited for a blend.
In the near future, Jacobson said, California’s grape growers should focus on areas with the lowest frost risk, stay away from regions with more forests (Napa versus Santa Ynez) and utilize those with plentiful ground water or access to storm runoff, such as Oregon, where rain is more routinely captured in ponds and tanks.