By Cameron Hewitt
Port is actually a British phenomenon, not Portuguese. Because Britain isn't suitable for growing grapes, its citizens traditionally imported wine from France. But during wars with France (17th and 18th centuries), Britain boycotted French wine and looked elsewhere. At that time Portuguese wines often didn't survive the longer sea journey to England.
It's said that the port-making process was invented accidentally by a pair of brothers who fortified the wine with grape brandy to maintain its quality during the long trip. The wine picked up the flavor of the oak, which the English grew to appreciate The British perfected port production in the succeeding centuries, hence many ports carry British-sounding names (Taylor, Croft, Graham).
In 1703, the Methuen Treaty reduced taxation on Portuguese wines, making port even more popular. In 1756, Portugal's Marquês de Pombal demarcated the Douro region — the first such designation in Europe. From that point on, true "port wine" came only from this region, following specific regulations of production, just as "Champagne" technically refers to wines from a specific region of France. Traditionally, farmers and landowners were Portuguese, while the British bought the wine from them, aged it in Porto, and handled the export business. But that arrangement changed in the late 19th century, when an infestation of an American root insect called phylloxera (which smuggled itself to the Old World in the humid climate of speedy steamboats) devastated the Portuguese — and European — wine industry.
In the Douro Valley, you'll see lasting 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.
Today, Porto and the Douro Valley see many British tourists. Though it's largely undiscovered by Americans, this region is a real hot spot among wine-loving Brits.
Cameron Hewitt is the co-author of several Rick Steves guidebooks.