Known and appreciated since the Middle Ages and earlier (wine-growing in the region has been traced back to 2,000 years before our time), Ribera del Duero wines were awarded the precious AOC in 1982. Thanks to a highly contrasting climate featuring very hot summers and rugged winters, the vineyard stretches across 12,000 hectares in northern Spain, across the regions of Castile and León (but not fully the length of the Duero as its name implies). It encompasses four provinces: Burgos, Segovia, Soria and Valladolid. Ribera del Duero wines are mainly red but the region is also home to some rosés produced from Tempranillo, Cabernet-Sauvignon, Merlot, Malbec, Grenache Noir and Albillo, a white grape variety. The reds are classified into four categories: young wines that have not been aged in barrels or aged in barrels for less than 12 months, "Crianzas", aged for at least 12 months in barrels, "Reservas" (aged for at least 36 months before being bottled, including at least 12 months in barrels) and finally "Gran Reservas" with a very long ageing process of 60 months (including at least 24 months in barrels and 36 in bottles). The legendary Vega Sicilia is undoubtedly one of the Ribera del Duero's most famous estates.