Making Fortified Wine
The practice of fortifying certain wines with extra alcohol developed in order to help them travel well. Fortified wines can be sweet or dry, depending on whether the spirit is added during or after fermentation of the base wine. Sweet or dry wines with 15% alcohol or more are usually made by adding brandy or pure spirit to the wine.
Dry Fortified Wines
Dry fortified wines, such as sherry, have the brandy added after the fermentation has finished. Varying amounts of sweet reserve wine are added back in before bottling, according to the style of sherry being made.
Sweet Wines
Sweet wines, such as Port, Madeira, Malmsey, Vermouth and Muscat de Beaumes de Venise are made by adding the spirit during the fermentation process.
About half way through fermentation, when the alcohol level is around 5%, a measure of spirit is added to the tank. This immediately raises the alcohol level, kills the yeast, and stops fermentation. All the unfermented sugar is left behind, resulting in a wine that is both strong and sweet. It is normally transferred to oak barrels at that point for ageing.
Fortified wines typically range from around 16 to 23% of alcohol - about double the strength of ordinary wines.
Popular Wines
Some of the most popular fortified wines include:
Sherry
Sherry, from Jerez in Spain, is perhaps the greatest wine made by the post-fermentation method. An unusual feature of sherry making is the "solera" system of ageing. In this system, wine from many vintages is matured in the cellars in separate casks. The casks containing the oldest sherry are constantly topped up with wine from the second oldest casks. These in turn are topped up with wine from the third oldest casks, and so on until the newest casks - from the current vintage. In this way, the style of sherry can stay much the same from year to year as all sherry is a blend of several vintages.
Port
Originating from the Douro valley of Portugal, port comes in various styles and quality levels. There may be a particularly good year two or three times a decade, when a vintage year will be declared and a vintage port is released. Vintage ports often take around 15-30 years after release to develop into truly great wines.
In comparison, LBV (Late Bottled Vintage) ports are ports that have been matured for longer than ordinary ruby or tawny ports. They are not true vintage ports of a great year, and are ready to drink when they are released.
Madeira
From the Portuguese island of the same name, Madeira is unique in the way that it is processed. Once it has been made (in the same manner as port), it is cooked. The wine is placed in very hot vats (over 50°C) for 90 days. This caramelises the wine, giving it a rich brown smoky flavour, with a startling acid bite.
