From the sun-baked black grapes of the Douro, to the sweet, golden Riesling clinging to shale slopes above the mighty Rhine, to the fog-shrouded Pinot that gently purples above the muddy banks of the Petaluma, the aristocratic rivers of the world's great—hold up now! The Petaluma? That slatternly slough that was made honest only through the gambit of a congressional bill? The very one.

But to be even less complimentary to Sonoma County's less celebrated, southerly river, it's actually what isn't there that matters more than the river itself. The Petaluma Gap, a space in between sun and fog where fog wins most of the time, is the source of much of this region's fine Sonoma Coast Pinot Noir and where Keller Estate Winery resides. Back in the 1980s, Keller Estate's founder arrived from Mexico, with a dream of someday owning his own vineyards and olive groves. Fortunately, Arturo Keller was a successful Mexico City industrialist, so it was a go. He even added a racetrack.

Nestled in the rolling hills above Lakeville, the charismatic debris of a one-time steamship port, the sprawling Keller campus looks like a small community college. The winery, designed by a prestigious Mexican architecture firm and built with stones rather expensively recycled from China's Three Gorges Dam project, is at the opposite end of the tasting room through a hand-dug cave; the natural lighting and horseshoe-shaped tank room may be of particular interest to wine-industry types. Visitors are likely to have the spacious hospitality room all to themselves, with no elbow forest in between them and their enjoyment of a lineup of excellent wines.

Keller Chards are on the subtle side, with the 2007 Oro de Plata Chardonnay ($30) having floral, earthy, wet mushroom aromas and fine, woody astringency, and the more viscous 2007 La Cruz Chardonnay, ($36) a seamless integration of fresh butter with oak. Plush, dark flavors of raspberry and cherry juice characterize the Pinot, with the 2007 La Cruz Vineyard Pinot Noir ($44) angling for plum, cola and dark spice, wrapping up with terry cloth tannins, and a long, fine finish reminiscent of the Oro de Plata Chard on the 2007 El Coro Pinot Noir ($52). Combine the best barrels of these, and get the 2006 Precioso Pinot Noir ($75), which adds spice and fennel with a bone thrown to bacon-fat fans. A deep violet rimmed with magenta, the silky, chewy 2005 La Cruz Vineyard Syrah ($40) brims with blueberry sauce and boysenberry fruit on the blacktop. Ah, the roasted slopes of the Rhone . . .

Keller Estate, 5875 Lakeville Hwy., Petaluma. Thursday-Sunday 11am-4pm, $10 fee. Call ahead. 707.765.2117.

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