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The annual grape harvest is wrapping up in California's wine country. And some wineries are considering a change. Prime areas like the Napa Valley could soon face rising temperatures, according to climate change studies. And that has some growers thinking of switching to grapes that are better suited to warmer weather.
But Lauren Sommer of member station KQED reports that adapting to climate change is a tough sell for vineyards that have staked their reputations on certain wines.
LAUREN SOMMER, BYLINE: Want to know how consumers pick a wine? Take the recent meeting of the San Francisco Wine Lovers' Group.
UNIDENTIFIED WOMAN #1: I like California Pinot Noir.
UNIDENTIFIED WOMAN #2: Usually, I'm drawn to Sauvignon Blanc.
UNIDENTIFIED MAN: Cabs, although I do like Pinots, but earthier Pinots.
SOMMER: The type of grape, or varietal, is how most of us think about wine.
ANDY WALKER: Ah, that's the big problem.
SOMMER: That's Andy Walker, a grape breeder at the University of California Davis.
WALKER: We've spent the last 100 years emphasizing varieties and we've really marketed those names very effectively.
SOMMER: We're walking through U.C. Davis' test vineyard, where hundreds of different wine grapes from around the world are grown.
WALKER: This is Petite Syrah.
SOMMER: The vast majority are unknown to consumers, because most wineries focus on only a handful of French grapes, grapes that prefer cool climates. Extreme heat can be the enemy of good wine.
WALKER: Well, it destroys acidity and it changes color and aromatics.
SOMMER: According to a recent study from Stanford University, about two degrees of warming could reduce California's premium wine growing land by 30 to 50 percent. That could happen as soon as 2040. Water supply is also expected to be an issue.
WALKER: I think the interesting thing for me as a breeder is to take advantage of this and say: OK, let's actually readapt varieties to California.
SOMMER: But Walker says grape breeding is frowned upon in the industry. Most vines are grown from a branch that's taken off an existing plant.
SEAN MYLES: This essentially means that grapes have not really been having sex very much.
SOMMER: Sean Myles is a geneticist at the Nova Scotia Agricultural College. He says breeding is big business for other crops, like corn. But wine grapes miss that opportunity to develop adaptability.
MYLES: That means that we're not allowing the genetic material to be shuffled anymore. That genetic material is now standing still in time.
SOMMER: You could crossbreed today's varieties to make them more heat tolerant or drought resistant. But U.C. Davis' Andy Walker says there's a big problem with that. Once you breed your Pinot Noir with something else, you can't call it Pinot Noir anymore.
WALKER: The last decision's the hardest. Can we market this variety?
SOMMER: Walker says there are wine grapes from Italy and Spain that would do well in a warmer California.
WALKER: We could produce Barbera instead or Negroamaro or Nero d'Avola from southern Italy and then we'd be far better ahead.
NICK DOKOOZLIAN: I think it's really a pull from consumers. In most cases, we're responding to consumer demand for a cultivar.
SOMMER: Nick Dokoozlian is a vice president at E and J Gallo Winery, the largest family-owned winery in the U.S. He says the company has been testing new wine varieties and has found some promising grapes.
DOKOOZLIAN: The problem is we can't necessarily sell those varieties. Consumers aren't aware of them. Really, the hurdles on the marketing side are much, much more significant.
SOMMER: Since vines can produce for up to 30 years, he says switching varieties is a major financial gamble.
DOKOOZLIAN: The wine business is an extremely capital intensive business. The financial risk of planting the wrong variety in the wrong place is pretty significant.
SOMMER: Still, given the temperature and water supply changes projected for California, Dokoozlian sees the market shifting eventually.
U.C. Davis grape breeder Andy Walker says it's up to the industry to make it happen.
WALKER: I don't think it's the consumer that's going to make the shift. They have to be directed.
SOMMER: Which means it could be some time before we see world class Nero d'Avola from California on store shelves.
For NPR News, I'm Lauren Sommer in San Francisco.
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