A panel of grapegrowing pundits held court last week during the Napa Valley Grapegrowers’ Rootstock trade show on the wisdom of relying so heavily on Cabernet Sauvignon.

While conditions in their line of work can vary widely year to year, as in the case of a fraught 2017 growing season, the panel noted that for growers in Napa at least one thing remains a certainty, for better or worse: Cabernet is here to stay.

Panelist PJ Alviso became vice president of Central Coast wine grapegrowing for Duckhorn Vineyards last year. Before that, he worked with the company’s Napa Valley vineyards for 12 years.

Looking at Napa from a distance now, Alviso mused, “The bastion that Napa has is pretty admirable.”

That bastion is essentially the branding of the valley and its tie to high-quality Cabernet Sauvignon, a position Alviso calls “unassailable.”

“We can chafe at there potentially being too much Cabernet,” he said. “We can chafe at various parts of what that means … We see cool vineyards with great varietals that we like to drink being ripped out and put into Cabernet. That’s happening for a reason and it’s happening because Napa Cabernet, that brand is so strong.”

Economically speaking, compared with Cabernet Sauvignon elsewhere in California, the varietal is safely set apart from the wider marketplace when grown in Napa.

For the first time in history, Alviso said, the wine grape market in Napa has decoupled from the rest of the California grape market. A situation, he said, “where what happens in the rest of the state doesn’t really affect Napa economically at all … I don’t see that changing moving forward.”

But how does the security in Cabernet affect other varietals in the valley?

While the valley offers a wealth of vineyard sites well-suited to produce quality Cabernet Sauvignon, there are also areas with climes and soils less than ideal for growing the region’s most profitable grape. For instance, a Cabernet Sauvignon grown in clay soils in a cooler area like Carneros may potentially be subpar to Cabernet Sauvignon grown on better soil profiles in warmer sites like the Rutherford Bench or Oakville.

And yet, while a site may be better suited for growing grapes other than Cabernet, the economics for growers are clear.

A member of the audience queried the panel: What might be the incentive for growers in Napa to plant a varietal like Sauvignon Blanc over the more lucrative Cab?

“There is none,” Alviso said.

Noting that Duckhorn Sauvignon Blanc from Napa Valley sells for $28 a bottle, Alviso explained, “We could not move that price up.”

“Sauvignon Blanc is not so much tied to Napa,” he added. “A consumer’s going to go, ‘Cool. This one’s from Sonoma and it’s $18. Why don’t I drink that?’”

While the profitability gap between varietals like Sauvignon Blanc and Cabernet could be balanced in the past by higher yields of the white grape, as the average price for Napa Cabernet has moved past $5,000 a ton, that model is no more.

“Now, no matter the yield difference, you’re making more money with Cabernet,” Alviso said.

An abundance of quality wines in the market could work to balance out those made with grapes grown in areas with sub-par conditions, Alviso said. “But,” he added, “you’re going to grow better Cabernet in OK ground in Napa than you are anywhere else in California and maybe the New World and significant parts of the Old World.”

However, panelist Jon Ruel, CEO of Trefethen Family Vineyards, cautioned growers against considering Cabernet as the end-all grape here.

“It’s not a monolithic market here in Napa Valley,” Ruel said. “You shouldn’t put Cab in the ground and expect $8,000 a ton.”

And as far as other varietals, Ruel urged growers to consider their ability to mitigate risk in the event of a poor year for Cabernet.

“What we need is a cold vintage,” Ruel said. “If we had a cold vintage and we were challenged in ripening in parts of Napa Valley, we’d remember some of the differences in our terroir.”

Conditions at Trefethen generally allow the vineyards to produce twice as much of varietals like Chardonnay or Sauvignon Blanc over Cabernet. Still, he acknowledged, half as much Cabernet as the other varietals could reel in more profit in a good year.

But when faced with a colder growing year, where slower ripening forces Cabernet to stay on the vines late into the season, the boon of earlier-ripening grapes would become obvious.

In those situations, Ruel said, “you’ve got a higher crop out there that’s struggling to ripen and you’re wishing you had Chardonnay and you already picked it.”