(Wines&Vines) - When Glenn McGourty, the winegrowing and plant science advisor for UC Cooperative Extension in Mendocino and Lake counties and Wines & Vines viticulture columnist, took his new post in 1994, someone suggested he conduct some unique research to differentiate himself. He shared some of that research Wednesday at a meeting of the Napa Valley Vineyard Technical Group, an organization of growers who meet regularly to discuss news related to grapegrowing.

His subject, alternate wine grape varieties, might seem an odd one for the Napa Valley, where Cabernet Sauvignon is widely planted, but he started his talk with a lesson—in this case about apples grown in Washington state. He noted that in 1986, red delicious apples represented 75% of the apple crop in that state, a leading apple grower. They were planted in 161,000 acres.

He said that red delicious are beautiful, bright red apples, but they aren’t delicious for long after they are removed from cold storage.

Other countries, notably New Zealand, started growing better tasting and better textured apples. By 2015, red delicious had dropped to 34% of the previous acreage, while the gala variety held 19%, Fuji 13% and granny smith 12%.

The analogy served as a warning to growers not to be complacent, noting that tastes change, as does the climate.

The lure of international varieties

McGourty continued that the “international varieties”—Cabernet Sauvignon, Merlot, Sauvignon Blanc, Pinot Noir and Chardonnay—became dominant outside Europe because they had a long history of export, were perceived to be high in quality and, of course, were traditional. “Monks optimized them, they didn’t have much else to do but pray,” McGourty noted, adding that the English became very interested in wine hundreds of years ago partly because it was safer to drink than the water they encountered.

But these international varieties weren’t necessarily ideal for the Mediterranean climates of major New World producers, including California.

The popular varieties came from continental climates that experienced more rain and cool weather than California. “For them, vintage years happened when the grapes become fully ripe. That wasn’t typical.