T he rise of fruit-driven, high-alcohol wines has been blamed on everything from the tip of wine critic Robert Parker's tongue to climate change. Global warming has been blamed on anything from the vagaries of the weather to Al Gore's Nobel Prize. Now, just when the words "scientific consensus" have begun to take root and grow in the poor, well-drained soil of public discourse, we may be in for a detour on the road to warmer days.

"Pacific decadal oscillation" (PDO) is the sexed-up scientific term. Climate scientists tentatively declared that we've entered a cool phase of the PDO last fall. The cyclical massing of colder surface waters in the eastern Pacific could hang out here for two or three decades, and it generally biases our climate toward cooler springs and more frost episodes (as seen this year), and maybe even those cloudy Augusts where every day is like Sunday. Since California's premium wine boom has taken place largely during the outgoing 30-year warm cycle, the suggestion is that, possibly, increasingly ripe vintages have had something to do with the weather, after all.

To get a preview of what to expect from cool climate wines, I trucked on down to Carneros. Bouchaine Vineyards was among the first to grow Burgundian cultivars on the wind-scraped hills north of San Pablo Bay. Originally founded by an Italian immigrant in 1927 who was unimpressed by Prohibition, the winery was bought by Burgundy enthusiasts in 1981 and got a handsome facelift in the 1990s with redwood lumber recycled from the old fermentation tanks.

Bouchaine's 2006 Gewürztraminer ($19) is sourced from Anderson Valley, another cool region that's getting hotter. It's dry and only mildly spicy, with a viscous thyme-infused-lemon character that could make for that rare artichoke pairing. A mellow mouthful of butterscotch under a thin haze of wood smoke, the 2006 Bouchaine Estate Napa-Carneros Chardonnay ($30) is enlivened with pine sap and grapefruit, and not even the 2006 Bouche de Beurre Chardonnay ($45) is an overbearing "mouth of butter."

The 2007 Pinot Gris, Carneros ($25) is but an ethereal wisp of fog on the tongue. My host said that their 2006 Pinot Meunier Estate, Napa Carneros ($35) has its on and off days; this day, the brilliant ruby wine nearly bounded out of the glass, perfumed with raspberry, finishing with astringent pomegranate. The classic 2006 Estate Napa-Carneros Pinot Noir ($45) is upstaged by neighboring 2006 Gee Vineyard Pinot Noir ($50); with a wild briary scent and cherry skin crispness that nearly crunches in the mouth. The 2005 Rockin' H Sonoma Coast Pinot Noir ($35) seems to have more in common with the 2006 Rockin' H Syrah ($30)—a brooding, plum- and cherry-scented wine with firm tannin—than its varietal brethren over the hill.

On a recent fair-weather day at Bouchaine with no PDO in sight, a number of winetasting parties enjoyed sunshine on the patio, and the busy staff kept an unfailingly great sense of humor throughout. With a hearth in the corner and rustic beams overhead, the country French interior would undoubtedly be a cozy redoubt on chillier afternoons—and like it or not, those chilly afternoons are coming, due to a phenomenon of low pressure oscillation that climatologists call "winter."

Bouchaine Vineyards, 1075 Buchli Station Road, Napa. Open daily, 10:30am–4pm; tasting fee $5. 707.252.9065.

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