Wikipedia Article About Port Wine on Wikipedia
Port wine (also Porto wine) is sweet, fortified wine from the Douro Valley in the northern part of Portugal; it takes its name from the city of Oporto, the centre of port export and trading. Port has been made in Portugal since the mid 15th Century. Port became very popular in England after the Methuen Treaty of 1703, when merchants were permitted to import it at a low duty, while war with France deprived English wine drinkers of French wine. The continued English involvement in the port trade can be seen in the names of many port shippers: Croft, Taylor, Dow, Graham, Symington. Similar wines, often also called "Port", are made in several other countries, notably Australia, South Africa, India and the United States. It has been made in and around St. Augustine, Florida since the mid 16th Century. In some nations, including Canada, after a phase-in period, and the countries of the European Union, only the product from Portugal may be labeled as "port." In the United States, the Portuguese product, by Federal law pursuant to a treaty with Portugal, must be labeled "Porto" or "Vinho do Porto" for differentiation.
Port wine is typically thicker, richer, sweeter, and possesses a higher alcohol content than most other wines. This is caused by the addition of distilled grape spirits (such as brandy) to fortify the wine and halt fermentation before all the sugar is converted to alcohol. It is commonly served after meals as a dessert wine, or with cheese. In France, white port is served as an apéritif. It has an alcohol by volume content of roughly 18% to 20%.