Pedro Rodríguez of Adegas Guímaro descends from a long line of    winegrowers    working in the Amandi area, Ribeira Sacra’s most prime subzone of perilously steep south facing vineyards planted on local    Losa    slate, just above the river Sil. The previous generation, his parents Manolo and Carmen, still work with him in the vines.    They named their winery Guímaro (meaning “rebel” in Gallego