Barolo has 2 valleys; 1) Serralunga valley: South and east villages Sand and clay, less fertile soil More austere, powerful wines Need min. 12 years ageing, very closed and tannic Key communes; Castiglione, Monforte d'Alba, Serralunga d'Alba 2) Central valley: North and west Blue-grey, calcareous marl Less tannic, less ageing, lighter, more aromatic. Key communes; La Morra (1/3 of production Barolo).