Port is a fortified wine that has its origins in the Duoro Valley. It is produced from various grape varieties, though Touriga Nacional, Tinta Barroca, Tinta Roriz, Touriga Francesca, and Tinta Cão are considered the best for the red port, while Viozinho, Rabigato, Arinto, Cedega, Gouveio are largely used for the production of white port.
After fermentation, the wine is fortified with brandy and is usually matured in oak casks. Depending on the style, after blending, the wine can further age in the bottle or the barrel. The most common port styles include the young and fresh Ruby, the earthy Late-Bottled Vintage, and the rich and smooth Tawnies, while the Vintage ports enjoy the highest prestige.