Dão is a Portuguese wine region situated in the Região Demarcada do Dão with the Dão-Lafões sub region of Centro, Portugal. It is one of the oldest established wine regions in Portugal. Dão wine is produced in a mountainous region with a temperate climate, in the area of the Rio Mondego and Dão rivers in the north central region of Portugal. The region became a Denominação de Origem Controlada (DOC) appellation in 1990. The Dão region is the origin of the Touriga Nacional vine that is the principal component of Port wine. This major region is in the heart of the Beira Alta and produces many red and white wines. The Dão region is to the east of the Bairrada region being geographically larger in size and covering 16 municipalities in the area between Viseu, Guarda and Coimbra. The vines are grown in valleys on slopes starting at an altitude of 200 mts. up to about 500 mts. The soil is basically granite which favours the red varieties. The reds are strong, deep in colour and full-bodied. The whites tend to be aromatic and fruity and some are bottled as sparkling rosé.