Douro

According to the Instituto da Vinha e do Vinho (IVV), vines were already grown in the valleys of the Alto Douro under Roman rule. On 10 September 1756 King José I and his Secretary of State, Sebastião José de Carvalho e Melo, the future Marquis of Pombal, founded the Companhia Geral da Agricultura das Vinhas do Alto Douro. The Port specification calls the result the first demarcated and regulated wine region in the world.

The Douro specification records that phylloxera reached the region in 1862. Before it, vines grew on small, irregular terraces with one or two rows held up by stone walls. Many of these were abandoned and are now called "mortórios". After phylloxera, growers built wider terraces. Horizontal terraces with earth banks ("patamares") came in the late 1960s and early 1970s, and later vines planted straight up the slope ("vinha ao alto"). The IVDP says the area below the Cachão da Valeira was divided into Baixo Corgo and Cima Corgo by the administrative reforms of 1936. UNESCO listed the Alto Douro wine landscape in 2001.

The region lies in the Douro basin of north-east Portugal and covers about 250,000 ha, of which about 43,800 ha are vineyard. It is divided into three subregions: Baixo Corgo (45,000 ha), Cima Corgo (95,000 ha) and Douro Superior (110,000 ha). The Cachão da Valeira gorge historically separated the upper river from the Douro Superior. The rules require vineyards on mainly schist soils, with granite patches allowed. The IVDP describes clay mixed with broken schist that lets water seep deep to the roots and holds the sun's heat; the soils are acid and poor in organic matter (about 1.5%).

The Marão and Montemuro ranges block humid west winds. Winters are very cold and summers very hot and dry. Annual rain falls from about 1,200 mm at Fontes in the Baixo Corgo to 380 mm at Barca d'Alva near Spain. The north bank, exposed to dry south winds, is warmer than the south bank. Mean annual temperatures range from 11.8 to 16.5 °C.

The Douro specification links the wines to the region's soil and climate and to its winemaking. It names soil, stoniness, altitude, sun exposure, climate and slope as the factors behind the range of Douro wines. Its native grapes, kept in great diversity, are named as a decisive element of their aroma and taste. Most reds are blends of several native varieties, with a profile the rules call characteristic of the Douro. The whites are also blends; they usually have good aromatic intensity and often ferment or age in wood. The rosés are made by light maceration of red grapes. The IVDP describes young reds as ruby with red-fruit aromas and wines for ageing as deep in colour, with black fruit, chocolate, balsamic herbs and firm tannins.

DO Douro covers still wine, sparkling wine and the fortified Moscatel do Douro. Its list of permitted grapes runs to more than a hundred varieties. The IVDP names Touriga Nacional, Touriga Franca, Tinta Roriz (Tempranillo), Tinta Barroca and Tinto Cão for reds, and Malvasia Fina, Viosinho, Gouveio and Rabigato for whites. Reds of good quality may be sold six months after 15 November of the harvest year; reds of very good quality need twelve months from 1 October. Sparkling wine must have its second fermentation in the bottle and stay at least nine months in bottle after it (Reserva at least twelve). Moscatel do Douro is made only from Moscatel Galego Branco, at 16.5-22% alcohol, and may carry age statements of 10, 20, 30 or more than 40 years. Douro wine may not leave the region or the Vila Nova de Gaia entreposto in bulk; it must be bottled there. Port shares the same region under its own designation.