Fortified Wines came along during wartime between Great Britain and France. The British, being at war with France, could no longer import their wine from France. As a result, they turned to Portuguese wines. However, they did not always make the voyage to England in pristine condition. They also were not the best tasting wines, especially to those who had been drinking the crème de la crème. To fortify them against the perilous sea voyage, Brandy was sometimes added to the wine. Soon it became common to fortify the wines with Brandy as the wine became sweeter, stronger, and more appealing to the English consumer. Thus, Port was born.
There are five main fortified wines: Port, Sherry, Vermouth, Madeira and Marsala. Madeira and Marsala are usually refered to as cooking wines.
There are three types of Port: Vintage, Tawny and Ruby. Vintage Port is aged in bottles after spending two years in oak. It retains a deep red/purple color and has sweet, ripe fruit flavors. Tawny Port is aged longer in oak, and tends to be brownish in color, which it gains from the oak. Tawny Ports have a nuttier, caramel taste with nuances of dried fruit, and the flavor becomes richer as the wine ages in casks longer. Ruby ports have a sweet, cherry candy flavor, reminiscent of fruitcake fruit and are aged in oak casks (but not as long as Tawny or Vintage). Ruby ports are typically designed to be consumed young.
Sherry is made from fortified white grapes. There are two basic styles of Sherries: Fino, which is bone dry, and Oloroso, which is nuttier and sweeter. As Sherry ages in casks, it develops a layer of flor, a yeast-like growth that helps protect the wine from excessive oxidation. This keeps the wine crisp and light in color. Oloroso, which undergoes aging, are fortified to reach an alcohol content of at least 17%. Incidentally, they do not develop a flor layer and do oxidize slightly as they age, giving them a darker color. Because the fortification takes place after fermentation, most Sherries are initially dry, with any sweetness being added later (such as cream Sherries).
Vermouth is a fortified wine flavored with herbs and spices, which may include cardamom, cinnamon, marjoram and chamomile. Sweet vermouths usually contain 10–15% sugar. Dry vermouths generally do not contain over 4% sugar. Dry vermouths usually have a lighter body than sweet vermouths. Vermouth is often added to vodka or gin to make martinis.