- an island in the Atlantic Ocean about 1,000 kilometres, or 625 miles, off the coast of Portugal. It is a DOC wine-producing area renowned for the famous fortified wine of the same name. It can be one of the longest-living wines in the world. Most Madeira is produced in an unusual way through heat and oxidation, which would usually spoil a wine. This process is called estufagem, or baking, and in effect accelerates the ageing of the wine. The more ordinary wine is placed in a lined concrete tank containing a stainless steel coil through which hot water circulates for at least three months; finer Madeira is placed in wooden casks and stored in a heated room for a longer time. The finest wine is not heated artificially at all, but is exposed only to the sun. The wine develops a slightly bitter, tangy taste and can vary in colour from pale gold to dark tawny. There are four different styles of Madeira: Sercial is light, dry and pale gold in colour; Verdelho is sweeter and stronger; Boal is sweeter, stronger and darker in colour; finally Malmsey is the sweetest and darkest. Sercial and Verdelho are normally served as an apéritif, Boal and Malmsey as a dessert wine. A historic medium dry style called rainwater is still also sometimes found.