Kunde Winery generally charges from $5 to $10 to sample its product, but free tasting flights are now offered monthly upon completion of a kind of wine country par course. The Sustainable Winegrowing Tour is a unique five-mile trek through the pastoral hills and vineyards of the Kunde Ranch, with commanding views of the Sonoma Valley and beyond. The 72 folks who showed up for the inaugural hike didn't need any vinous encouragement, but at the end of the trail, it probably helped.

The tours are led by docent Bill Myers, a Kunde neighbor and veteran leader of state and regional park-sponsored hikes. Comprising 1,850 acres, with more than 700 in grapes, Kunde is one of few family-owned operations of this scale. The trail begins in vineyards and winds past bellowing cows, their calves blinking with a glimmer of curiosity, then skirts a series of lakes. Ski Lake suggests it wasn't always work and no play down on the ranch. A Kunde employee who happened to be along helped fill in commentary on the land and history. We learned, for instance, that C.S. Ridge is not exactly named for Cabernet Sauvignon (and not for cow something-or-other, but you're close). In a peaceful clearing, the historic ruins of the Dunfillan Winery remind us that award-winning Cabernet Sauvignon was being made here back in the 1880s. We crossed cattle grates, and at one point, a field of bulls fortunately disinterested in our trespass.

As for sustainable winegrowing, there are owl boxes, and the vineyards are irrigated using rainwater collected in lakes. This is sustainable we're talking about, not cowhorns and crystals (the horns are in fact still affixed to the cows at this working ranch), and the general picture is of good stewardship of this beautiful land. Kunde is one of 12 wineries in the county to be distinguished with Second Level Green Business Certification.

Complimentary or not, I wasn't looking forward to jostling with tourists at the tasting bar after four hours of hilly hiking. Turns out Kunde had arranged a whole spread just for us on the adjacent terrace. It's like a thank you for enjoying the views! I alone could have drunk a chilled carafe of the 2006 Magnolia Lane Sauvignon Blanc ($15), a sweet, moonshine-pale nectar tasting of pineapple and starfruit. (When was the last time I had starfruit? I don't recall, but it sure sounds right.)

The 2004 Meritage 202 ($40), balanced and mild, plummy with a grape twist, is much as I imagine a fine California Claret would be described in a dispatch from the turn of the last century.

Kunde Estate Winery and Vineyards, 9825 Sonoma Hwy., Kenwood. Tasting room open daily, 10:30am to 4:30pm. Fees, $5-$10. Free hiking tours and tasting Saturdays, June 9, July 14, Aug. 11, Sept. 8, Oct. 13, Nov. 10 and Dec. 8. Kunde also offers Eco Tours with Jeff Kunde, which cost $75 and include lunch. 707.833.5501.

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