Yes, it's a castle! Complete with crenellated parapets from where the defenders can fire arrows at attackers and douse them in boiling oil. All that's missing is a drawbridge over a moat, but the castle is surrounded by grape vines and not many 'real' castles have those.
Experience a taste of Napa Valley with a wine tour led by knowledgeable guides. They take you deep into the castle to learn about the complex process of making wine. Admire the 42,000 bottles of red and white wine varieties in the cellars, kept at 16 degrees centigrade for the whites (sauvignon blanc, chardonnay and semillon) and 14 degrees for the reds (cabernet sauvignon, syrah and merlot). The reds are graded by number according to quality, from the cheapest "classic" varieties through the 55, 66, 77 and 88 labels up to the top-of-the-range 99.
All wines are available for purchase in the tasting area. Tour-ticket prices are reimbursed if you buy the 88 or 99 varieties.
The tasting area, café and indeed the whole castle can be hired for special events. There's also a supermarket that sells wines and food.
The RD Wine Castle is open from 7:30am seven days a week and closes at 4:30pm Monday to Thursday, 7:30pm Friday to Sunday.