Ribera del Duero

The specification starts with the Vaccaean-Roman site of Pintia, between Padilla de Duero and Pesquera de Duero, where residues in vessels show that wine was served and drunk by the fourth century BC. A Roman mosaic of 66 m² with Bacchic scenes was found at Baños de Valdearados during the 1972 harvest. The link with wine grew in the tenth and eleventh centuries, when San Esteban de Gormaz, Roa, Aranda de Duero and Peñafiel were founded. By the twelfth century monks made wine at Valbuena de Duero, Caleruega and La Vid. Cellars dug under the villages appear in the thirteenth century, the harvest was regulated from 1295, and the Ordenanzas of Castile of the fifteenth century set rules on production and trade. The first Reglamento of the designation was approved by order of 21 July 1982 and the present one on 1 December 1992.

The designation lies on the northern Castilian plateau where Burgos, Segovia, Soria and Valladolid meet. The Duero links more than 100 villages along a vine-growing strip about 115 km long and 35 km wide. The basin formed at the end of the Mesozoic and filled during the Tertiary with detrital and evaporitic sediments: lens-shaped layers of silty or clayey sands with alternating limestones, marls and calcareous concretions. Today it is a gently undulating peneplain, with hills up to 1,014 m and valleys mostly between 750 and 850 m. Common soils are ochre and reddish sandy clays and the middle and low terraces of the river, with basic pH and little organic matter.

The climate is described as Mediterranean with a strong continental character and Atlantic influence. Extremes run from 42 °C to -20 °C, frost is possible from 17 September to 6 June, and day-night swings reach 15-20 °C during ripening. Rain is moderate to low, about 435 mm at Aranda de Duero, with dry summers.

The specification calls the area a "limit zone" for quality wine, where yields, varieties and site have to be adjusted. It links the high average altitude, slow ripening and wide day-night swings to good formation of aroma and colour compounds by day and less loss of them at night, and to a natural softening of tannin. More than 2,400 hours of sun and summer heat build polyphenols. The result, it says, is balanced natural acidity and, in reds, deep colour with bluish tones from anthocyanins and vitisins, and polymerised tannins. Young wines are bright and fruity; aged reds keep bluish tints for a long time and join the fruit of Tinto Fino to oak. Albillo Mayor whites are aromatic, with fruity or green notes and fresh acidity.

Permitted grapes are Tempranillo (accepted synonyms Tinto Fino and Tinta del País), Cabernet Sauvignon, Garnacha Tinta, Malbec, Merlot and Albillo Mayor. Tempranillo is the principal red grape and Albillo Mayor the principal white. Reds must contain at least 75% Tempranillo, rosados/claretes at least 50% red grapes and whites at least 75% Albillo Mayor. Old vineyards planted before 21 July 1982 may include scattered vines of other local varieties.

Crianza reds age 24 months with at least 12 in oak, Reserva 36 months with at least 12 in oak and Gran Reserva 60 months with at least 24 in oak; the rest is in bottle. Barrels for these terms hold at most 330 litres. "Roble" or "Barrica" wines need at least three months in casks of up to 600 litres. Ageing cannot be counted before 1 October of the harvest year. Maximum yield is 7,000 kg/ha (9,500 kg/ha for Albillo Mayor).