Climate change could see end of Cabernet Sauvignon's dominance in Napa Valley
The future of Cabernet Sauvignon is at stake in Napa Valley, where rising temperatures, interimittent drought and frequent wildfires are all threatening the varietals’ future in the Californian region.
As a result, some winemakers are taking matters into their own hands by planting experimental vineyards — and, in some cases, acknowledging that Napa Valley's future may not lie solely with Cabernet.
“I hear some wineries saying, ‘We’re going to have to start thinking about different grape varieties in 30 years,’” Dan Petroski, winemaker at Larkmead Vineyards in Calistoga told the San Francisco Chronicle. His disbelieving resonse: “You’re going to start thinking about it in 30 years?”
Like nearly all Napa wineries, Larkmead produces mainly Cabernet, which accounts for nearly three quarters (73% ) of its total vineyards. Since Petroski started working for the winery in 2006, he has seen higher temperatures shift the annual Cabernet harvest almost four weeks earlier.
In the long term, however Petroski believes that as temperatures climb ever higher and the harvest shifts to earlier in the year, grapes will become overripe in their sugar accumulation while still remaining under ripe in their flavour development.
"Theres going to come a point with Cabernet in Napa where you have it seared on the outside and completely raw on the inside,” said Petroski, who thinks that Larkmead has another 20 to 30 years before the winery’s reliance on Cabernet alone becomes unviable. As a result, it is experimenting iwht a three acre parcel of land with some grape varieties which are better able to withstand higher temeratures than Cabernet including Charbono, Zinfandel, Petite Syrah and Chenin Blanc.
“Napa has already moved into another climate category,” according to S Kaan Kurtural, UC Davis professor of viticulture and enology, by which he is referring to the Winkler Index, a scale that outlines what types of grape varieties can grow within certain temperature bands.
While Cabernet Sauvignon can grow successfully in the Winkler’s Index’s Regions II, III and IV, region V would be pushing things too far. In 1944 when the system was developed most of Napa Valley was categorised as on the cool side of a Region II; now most areas are warm Region III or even a Region IV.
Meawnhile, Spottswood Winery owner Beth Novak Milliken agreed that Cabernet alone is not the answer. “Napa Valley will continue to be a strong grape growing area, but will it be Cabernet dominant,” she questioned. She is now searching for land in cooler zones where she could invest in future Cabernet vineyards. Meanwhile, she is also experimenting with different grape vareitals, better able to withstand higher temperatures.
However, Petroski is dubious that the industry at large will take action. “A lot of the resistance to addressing climate change is the cultural fear for changing what we love bout Napa Valley, “ he said. “Napa is Cabernet. It’s not going to suddenly become Aglianico.”
He points to Bordeaux as inspiration for the future as another wine region based on Cabernet sauvignon, where wines are identified by the winery rather than grape varietals. “Our brand should be Napa Valley red wine, not Napa Valley Cabernet Sauvignon,” added Petroski.