A pioneering effort were made in the 1970s which identified Touriga Nacional, Tinta Roriz, Touriga Franca, Tinta Cão and Tinta Barroca as the prime dark-skinned grape varieties.
En pionjärinsats gjordes på 1970-talet som identifierade Touriga Nacional, Tinta Roriz, Touriga Franca, Tinta Cão och Tinta Barroca som de främsta blå druvsorterna.