What amounts to Napa County wine family royalty will build a Chiles Valley castle of a winery.

Carolyn Martini and her husband, Barry Cox, on Wednesday obtained Napa County Planning Commission approval to build Castlevale. The winery will look like a medieval castle, but one far more modest than Dario Sattui’s grand Castello di Amorosa, a major tourist attraction on Highway 29.

Martini is the granddaughter of Louis M. Martini, who established his famous, eponymous winery just south of St. Helena along Highway 29 in 1933. The family sold Louis M. Martini Winery in 2002 to the Gallo family, whom Carolyn Martini called “long-time family friends.”

Now, Carolyn Martini and Cox, along with their son Hollsted Cox and his wife Jennifer Cox, plan to produce up to 30,000 gallons of wine annually at Castlevale.

“This little winery will complete our heritage,” Carolyn Martini said.

The winery castle design is based on the castle design of the nearby Martini-Cox house. Carolyn Martini said after the meeting that her husband came up with the idea for the house that was constructed three decades ago.

“It was really Barry’s every-boy-should-have-a castle dream,” she said.

Cox built a model of his planned house out of Legos when figuring out the proportions, Martini said.

Castlevale winery will be 22,051 square feet and 35 feet tall with a 50-foot-tall tower. It will have a small tasting area inside the building and hold some marketing events on a rooftop terrace with views of the surrounding vineyards and mountains.

Built into the hillside, the winery will be made from limestone plaster over cast-in-place concrete, with wooden timber and trim on architectural features and a flat clay tile roof.

“It’s very functional,” consultant Donna Oldford told the Planning Commission. “But it’s their dream, so it follows the winery would be a castle winery.”

The Planning Commission by unanimous vote did its part to make the Martini-Cox dream come true.

“This project is kind of the continuation of a local legacy,” Commissioner Dave Whitmer said. “The Martini family is well-known in this valley and has been for a quite some time in helping to shape this place.”

Castlevale helps take that important legacy to the next generation, he said.

Commissioner Terry Scott said the winery is unique beyond the family history. He also noted its location at 3450 Chiles Pope Valley Road in Chiles Valley, which is one valley east of the upper Napa Valley.

“That is not part of the beaten track,” Scott said.

Commissioner Jeri Hansen asked the family to consider installing an electric vehicle charging station in the parking lot. The family agreed to install the station.

Castlevale is to include a 2,965-square-foot cave. It can have 6,552 tasting room visitors annually and 835 marketing event guests annually, for total annual visitation of 7,387. It will be on a 55-acre property, of which 30 acres is vineyards.