In 1987, Jim Summers acquired a 28-acre vineyard nestled in Knights Valley, a region located northwest of Calistoga between Mount St. Helena and the Alexander Valley. At the time, the property was predominantly planted with Merlot grapes, established 30 years earlier by Dan Duckhorn, along with some Muscat Canelli. The inaugural vintage of Summers Ranch Reserve Merlot was produced in 1992, yielding 900 cases. Today, the estate also produces Petite Sirah from the Knights Valley vineyard. Known for its warm climate, volcanic soils, and proximity to Napa Valley, Knights Valley has recently garnered increased attention for its Bordeaux varietals.

In 1996, Summers expanded their vineyard holdings by acquiring 25 acres at the intersection of Highway 128 and Tubbs Lane in Napa Valley. This property, now known as Summers Estate Wines, is home to the Villa Andriana Vineyard, named in honor of their daughter. While the estate has been fully revitalized to maximize its potential, the 40-year-old Zinfandel vines are meticulously preserved. The winery and tasting room, surrounded by over 22 acres of Zinfandel, Charbono, and Cabernet Sauvignon vines, strike a perfect balance between pleasure and productivity.

Summers' signature wine is the distinctive Charbono, a varietal believed to be an early Italian adaptation of Charbonneau, a French grape. Some argue it is closely related to the Dolcetto variety, which is commonly grown in northern Italy. The Charbono vine produces large berries that create a deeply colored red wine, known for its rich fruit flavors and low tannin content when subjected to extended skin contact during fermentation.

The Summers Estate, with its scenic vineyard views in Calistoga, California, stands as a testament to the region's rich winemaking heritage.