From Wine Spectator magazine
Spain's major contribution to red wine, Tempranillo, is indigenous to the country and is rarely grown elsewhere. It is the dominant grape in the red wines from Rioja and Ribera del Duero, two of Spain's most important wine regions.
In Rioja, Tempranillo is often blended with Garnacha, Mazuelo and a few other minor grapes. When made in a traditional style, Tempranillo can be garnet-hued, with flavors of tea, brown sugar and vanilla. When made in a more modern style, it can display aromas and flavors redolent of plums, tobacco and cassis, along with very dark color and substantial tannins. Whatever the style, Riojas tend to be medium-bodied wines, offering more acidity than tannins.
In Ribera del Duero, wines are also divided along traditional and modern styles, and show similarities to Rioja. The more modern-styled Riberas, however, can be quite powerful, offering a density and tannic structure similar to that of Cabernet Sauvignon. Toro is an emerging region that is proving an ability to deliver high quality Tempranillo-based reds, with ripe fruit and impressive power.
Tempranillo is known variously throughout Spain as Cencibel, Tinto del Pais, Tinto Fino, Ull de Llebre and Ojo. It's also grown along the Douro River in Portugal under the monikers Tinta Roriz (used in the making of Port) and Tinta Aragonez.
Drought- and heat-resistant, Grenache yields a fruity, spicy, medium-bodied red wine with supple tannins. While it is widespread in France's Southern Rhône Valley, it is also important in Spain, where it's known as Garnacha Tinta. Grenache is especially noteworthy in Rioja (where it is a secondary grape in wines dominated by Tempranillo) and Priorat (where it often takes the lead in blends that may also contain Cariñena, Cabernet Sauvignon or Syrah). Campo de Borja has recently shown an ability to make rich, fruity wines from old-vine Garnacha.
Grenache Blanc, known in Spain as Garnacha Blanca, is in various Spanish whites, including Rioja.
Monastrell is best known as Mourvèdre, used in France’s Southern Rhône Valley, but this red grape is indigenous to Spain, where it flourishes in the sandy soils of the Jumilla district, in the southeastern part of the country near Valencia. Well-made examples show chewy tannins, spicy cherry and berry flavors and a characteristic gamy, meaty or smoky note.