Leaving the familiar green scene of the valley floor, Soda Canyon Road runs past ramshackle ranchettes and mini-mansions before ascending the rugged hills east of Napa Valley. Oaks yield the peaks to coyote bush, the thin soil to bare rock, and the odd stand of Burbank spineless cactus completes the picture. This looks more like Old West cattle country than wine country, and hardscrabble at that. Then, a verdant valley appears, a viticultural land of the lost carpeted with vines not quite as far as the eye can see—on a clear day, the eye can see to San Francisco.

The story of Stagecoach is one of extremes and engineering feats. Two miles end-to-end. One billion pounds of rock extracted. Planting by way of dynamite. Eleven wells dug to the specifications of a water witch. One hundred seventy-five combinations of grapes and rootstock. Amid what amounts to a remote city of grapes, it would seem doubtful that any one person could keep track of it all. Yet when asked if there's any Grenache hereabouts, viticulturist Amy Warnock promptly replies, "Block C2, Alban clone, on Schwartzman."

It's what's not extreme that draws seventy wineries to this site. Although cooler than the valley below, the vineyard is above the fog line, and the ripening grapes experience less dramatic temperature swings throughout the day.

Jan Krupp hadn't envisioned such an undertaking when he started out in 1991. But sensing the demand for grapes from these soils, he partnered with businessman brother Bart to look for more vineyard land, the only parcel available being 750 acres just to the north. Stagecoach grapes are now sold at a premium, while the Krupp Brothers release their own label of some 2,000 cases.

The 2006 Black Bart Marsanne ($35) is a honey-hued wine with a doozy of an aroma, all the oak and melted butter of a big Chardonnay, with caramelized pecan, honey, baked pear and apricot. Starts exotic, but draws one in with a rich palate of orange oil, papaya and Meyer lemon. The 2006 Veraison Napa Valley Cabernet Sauvignon ($34, 375ml) has aromas of spicy Christmas cake, dark roasted chicory, dried fruits, with very fine and dry forward-palate tannins.

Krupp Brothers Estates, 3265 Soda Canyon Road, Napa. Vineyard tours by appointment only, $25. 707.260.0514. Tasting available daily at A Dozen Vintners, 3000 Hwy. 29, St. Helena. 10am–5pm. 707.967.0666.

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