Some experts claim that centrally-located Ribera del Duero, Spain's fastest growing wine region, has the greatest potential for memorable red wines. These are largely inspired by the revered Vega Sicilia, an estate producer whose dark Tempranillo wines are balanced with 20% Cabernet Sauvignon. For one hundred years Vega Sicilia has taken Spanish tradition to the extreme, growing highly concentrated grapes and aging wines ten years in cask and sometimes more in bottle before releasing exquisite, expensive wines that still benefit from cellar aging. Like slightly smaller versions of Vega Sicilia, other Ribera del Duero Tempranillos are tannic and long-lived, usually inky and massive, with complicated aromas of chocolate, plums and smoke. French varietals Cabernet Sauvignon, Merlot and Malbec are joining the native varietals. White Ribera del Duero uses the indigenous varietal Albillo.