According to the Method of Punctuation of the Plots of Land of Vineyards of the Region of Douro (decree nº 413/2001), there were 30 recommended and 82 permitted grape varieties in Port wine production. The quality and characteristics of each grape varies with the classification of grape varieties making a distinction between "Very Good", "Good", "Average", "Mediocre" and "Bad" quality grapes. But this classification is actually in revaluation based on the technical and scientific data of the CEVD (Center of Wine Studies of Douro). The six most widely used grapes for red Port wine are Touriga Franca, Tinta Roriz, Tinta Barroca, Touriga Nacional, Tinta Cão and Tinta Amarela.[1]
