THE LATE Donald Rumsfeld’s famous (and famously convoluted) obiter dictum about “known unknowns” referred to history, but it could have referred just as aptly to wine and the pleasure of endless new discoveries. A personal recent discovery is Verdejo, Spain’s fourth most widely planted white wine grape, found mainly in the region of Castile and León in north-west Spain, around three notable cities: Valladolid, home of the Royal English College; Segovia; and Ávila, home of the first female Doctor of the Church, St Teresa. The town of Rueda gives its name to the denominación, a designation dating only from 1980, when Verdejo was rescued from primitive, bulk production methods by massive investment from the great Rioja house, Marqués de Riscal.