In 1976, Ramos Pinto began a detailed and ongoing research project to select the best grape varieties for the production of quality Port. Five varietals selected by Ramos Pinto were subsequently adopted by the Authorities for all new plantings in the region: Touriga Nacional, Touriga Francesa, Tinta Barroca, Tinta Roriz and Tinto Cao. Following ageing of the two to three years at the lodges in Ramos Pinto's Quintas in the Douro Valley, the wines acquire a specific character. They are then brought down to the Vila Nova de Gaia and blended according to the desired style. Port production is governed by very strict regulations whcih guarantee the authenticity of the wines. The Port Wine Institute grants the producer a certificate of origin and a seal of quality only after each blend has been tasted, analysed and approved for export.