The early 1800s was a watershed era for the vintners of Portugal’s Douro Valley, On one hand, the grape harvest of 1820, after fermenting and aging for four years, presented connoisseurs with a wine of remarkable sweetness, with “plenty of crust and plenty of color…and a well-stained cork,” according to T.G. Shaw, who recorded his views in Wine, the Vine, and the Cellar (1863), The exceptional vintage established Portuguese wine as a favorite among the British.
On the other hand, the 1820 harvest set a high standard, one that subsequent vintages could not attain. Merchants adulterated subsequent years’ production, adding elderberries to give the thin wine color and body and sugar in a vain attempt to match the sweetness of 1820.
It was a repeat of the 1750s when overproduction and falling prices tempted winemakers to cut corners on quality and methods. Seeking to return Port to its rightful place among elite wines, the Marquis of Pombal demarcated and classified the Port vineyards, regulated production stamped out fraud and established trade restrictions.
That England accepted Portugal’s wine at all was a consequence of one its many tiffs with France. The two powers had been trading sanctions and countermeasures for decades when, in the late 17th century, Britain decided to hit its continental rival where it hurt – in the wine industry. Deprived of rich Bordeaux, the British established closer trade relations with Portugal and its wine merchants.
The long, arduous journey from the valley to Oporto and thence to England took its toll on the wine, and merchants often added small amounts of brandy before loading onto the ships to stabilize it and add longevity. Though a vocal minority decried the process, vintners soon learned that this fortification, though merely an expedient at the time, expedited and improved the aging process of Port. Adding the distilled spirit during fermentation also increased Port’s sweetness and aroma. Henceforth fortification with brandy became the hallmark of port wine and ushered in an era of prosperity and popularity that lasted through the middle of the 19th century, withstanding Napoleon’s occupation of Oporto and the Portuguese Civil War
Cheap imitations came from France, Germany and Spain
As with all Western European wines, the boom ended with the Phylloxera infestation in the late 1860s. By the time the Port industry fully recovered at the turn of the century, cheap imitations from France, Germany, and Spain had claimed a large share of the market, prompting Prime Minister Joao Franco to establish strict rules governing Port’s production, regulation, and sale.
Port’s position as one of Europe’s great wines is the culmination of a great journey. The hills of the Douro Valley have been producing the grapes that make Port for 2,000 years, under the influence of the great ancient cultures. The wine has been traded with neighboring peoples since the 12th century. The ties between Portugal’s wine industry and Great Britain extend to the 1386 Treaty of Windsor when the weak vintages of Viana do Castelo proved too raw and sharp for English palates. The search for sweeter, mellower wines led to the development of the Douro farther inland, and the need to fortify the casks with brandy.