The region experiences abundant rainfall in the winter months and long, warm dry summers leading up to harvest.

Considered to be "the most enlightened viticulturist of his generation", he modernized the processes of winemaking and raised the standards of the wine produced in the region.

These co-operatives would have exclusive privilege to the grapes grown in the region and were charged with making the wine that would be sold to private merchants.

In 1979, Portugal's application to the European Union prompted authorities to overturn these rules, as the EU discouraged monopolistic practices in the wine industry.

[2] The area is home to several dozen varieties of indigenous grapes, with the majority of wine production being made from the Touriga Nacional,[3] Tinta Roriz, Jaen, Alfrocheiro Preto and Encruzado.

[4] Another reserve designation, Garrafeira, requires wines to be 0.5% higher in alcohol content than the 12.5% minimum and to spend at least two years in aging in oak.