Eight hundred feet above the valley floor, on a plateau of volcanic rhyolite where St. Helena meets Rutherford, sits the small block that makes Snowden’s most serious wine. The family bought this 160-acre mountain ranch in 1955 and gave much of it back to forest preserve, farming only about 23 acres. Diana Snowden Seysses, third generation here and a winemaker at Burgundy’s Domaine Dujac the rest of the year, ferments with native yeasts and ages the wine nineteen months in French oak. The result is Napa Cabernet with cut: dark, mineral and structured rather than plush. Just 332 cases were made, and it will reward a decade of patience.