2015 Six Sigma Ranch Diamond Mine Red Blend 750 ml

Robust Case–Buy Red from Napa’s Next-Door Neighbor

Here’s an iron-clad tip: When the Beckstoffers, the first family of Napa Valley winegrowing, expands their holdings in a new area, you can bet they’re onto something special. The Beckstoffers are stewards of Napa’s most storied sites, including To Kalon, Missouri Hopper, and Dr. Crane. Their investment in the volcanic Red Hills of Lake County, the extreme high-elevation Napa neighbor, is what we’re talking about. Wines bearing the Beckstoffer fruit are already selling north of $50 a bottle. But this 2015 Six Sigma Diamond Mine Cuvée, also from Lake County, is the full-bodied, cherry-scented and generous under-$30 gem that thrilled Wine Access members when we offered it the first time. This edition, from Robert Parker’s “extraordinary” 2015 North Coast vintage, is sure to win just as many fans.

California’s Lake County keeps rising as savvy wine consumers look to Napa’s high-elevation neighbor to the north for what is becoming a rarity in the state’s marquee wine region: High-quality red wine at a reasonable price. What is it that makes Lake County such a viable option, both for consumers and for the Napa Valley winemakers who bolster their wines with Lake County grapes? It’s simple: Napa Valley Cabernet averages roughly $7,500 per ton, and skyrockets from there to prices north of $35,000 a ton. As for Lake County grapes, they cost less than a tenth of their Napa counterparts. 

The geographical differences between the two regions are nowhere near as stark. The Mayacamas Mountains, which create the western ridge of Napa Valley, continue up into Lake County, where the same red volcanic soils that are prized in Napa also occur. As one Lake County winemaker recently told Esther Mobley of the San Francisco Chronicle: “The grapes don’t know which county they’re in.” 

Napa’s Lake Berryessa is visible from the plateau at Six Sigma’s Diamond Mine Vineyard, which is rich in the red volcanic soil that is ideal for both Tempranillo and Cabernet Sauvignon. The property’s 1,700-foot elevation helps keep wines lively by facilitating extreme diurnal temperature variations: in the weeks leading up to harvest, it’s common for the temperature at Six Sigma to reach 95°F during the day, plummet to 45°F at night, and then rocket back up with the rising sun. The result is grapes that recall the best of Spanish Tempranillo: fabulously ripe and balanced beautifully by generous acidity.

Winemaker Sandy Robertson has parlayed Six Sigma’s stellar fruit, and his experience working with California legends Merry Edwards and Dan Goldfield, into a round, robust, and structured blend inspired by one of Spain’s most revered wines—Vega Sicilia’s $400 “Unico,” which also combines Cabernet with Tempranillo. Aged for 18 months in mostly new French oak, the Diamond Mine Cuvée boasts ripe plum and cherry, cinnamon, oak, and a long, firm finish. 

Finding a blend like this in neighboring Napa Valley—from this top vintage and at this price—is not in the cards. A perfect match for grilled meats, BBQ, and rich cheeses, this is a wine to stock by the case, and open whenever the urge strikes you.