PSI is an outstanding offering from Peter Sisseck in Ribera del Duero. He is best known for his top tier wine Pingus ($1000+) and the Flor de Pingus ($100+) but the PSI is for the rest of us. He works closely with a cadre of grape growers to help protect various plots of various very old vine Tempranillo. They work primarily organically or biodynamically and the resulting wine shows an elegance and finesse that is atypical of the powerful wines of the region.