The history for wine grapes is relatively short. Official status was not granted until 1982 and prior to this there were not a lot of quality producers in the region. However, they have quickly achieved status as a quality wine region. Much of this success is attributable to the Tinto Fino or Tinta del Pais grape, a variant of Rioja’s Tempranillo. It seems to have adapted very well to the Duero’s climatic extremes and produces deep colored, occasionally astringent, firm flavored red wines without the aid of blending other grape varieties.
The Duero valley averages about 2600 ft. above sea level. This makes for a relatively short growing season. Temperatures reach extremes during the season, with very hot summer days ‐ up to 104° ‐ but they fall sharply at night. These extremes however, seem to be a positive factor when it comes to making high‐quality wine. It is widely believed that these conditions combine with the mountain air of the Duero to help Tinto Fino to retain more acidity than Tempranillo wines from other parts of Spain, and thereby provide the resulting wines with great structure and longevity.
Other grape varieties which are used in Ribera del Duero include Cabernet Sauvignon, Merlot, Malbec and Garnacha. How‐ ever, the first three are theoretically confined by law to vineyards which were planted in the last century.
The soil is generally loose and easily worked. There is a good deal of limestone, and often iron too, which explains the red‐ dish hue of the soil. Vineyards closer to the river are known to have a considerable clay content.