Silver Oak Cellars Producing only two wines, the Napa Valley Cabernet Sauvignon and the Alexander Valley Cabernet Sauvignon, Silver Oak has long been a staple on steakhouse wine lists and among expense-account diners. These high-prestige, fashionable wines are generally medium-bodied and smooth, with exotic suggestions of bourbon, cocoa butter and chocolate from the American oak barrels in which they are aged for 30 months or longer. Though Silver Oak's wines were once difficult to obtain, production, especially of the Alexander Valley bottling, is now quite large.