Douro full day private tour 

Surprisingly, Port is actually a British drink and not Portuguese. Because Britain wasn't suitable for growing grapes, Britain imported wine from France. However, during wars with France (17th and 18th centuries), Britain boycotted French wine and searched elsewhere. At that time, the wines from Portugal often couldn't survive the long sea journey to England.

Historically, port-making process began accidentally by a pair of brothers who strengthened the wine with brandy to ensure its quality during the long trip to England. The wine absorbed the flavour of the oak barrel, which the English grew to appreciate.

The British perfected the port production in the following centuries, thus, many ports carry British-sounding names (Taylor, Croft, Graham).

In 1703, the treaty of Methuen lowered taxation on Portuguese wines, making port more popular. In 1756, the Portuguese Marquês de Pombal demarcated the region of Douro — which was the first designation anywhere in Europe. From this point on, true "port wine" could only come from this region, following certain regulations of production, the same as "Champagne" technically refers to wines from a specific region of France. 

In the 19th century, the area and much of Europe was devastated by and insect called phylloxera and the Douro Valley, which you will see evidence of the phylloxera infestations in the "dead" terraces, overgrown with weeds and a smattering of olive trees. During the infestations, these particular terraces were treated with harsh chemicals that contaminated the soil, rendering it no longer suitable for grapes. Other terraces were left untouched, as Portuguese vintners simply gave up. Unable to produce usable grapes for over a decade, they sold their land to British companies who were willing to wait until a solution could be found. It was, as phylloxera-resistant American rootstock began to be used throughout Europe. Port production resumed, this time on British-owned land.