Everything you think you know about Garnacha, that it is jammy and hot and heavy, comes undone in the Sierra de Gredos. Up in these mountains west of Madrid, on cold granite at altitude, the grape turns light on its feet: red fruit, wild herbs, crushed rock and a savory snap at the end. Juanan Martin farms dozens of tiny old-vine parcels around the village of Burgohondo, working biodynamically and keeping his hand light in the cellar. Barrera de Sol is one of his named-site reds, medium-bodied and mineral, with the kind of nervous energy that has you pouring a second glass before you have decided to. Give it a light chill and it gets even better.