Wine Basics - Fortified Wines
The term fortified indicates that the wine's alcoholic strength has been boosted by the addition of spirit, usually a grape-based spirit, like brandy. Fortified wines can be sweet or dry, depending on whether the spirit is added during or after fermentation of the base wine. The family of sweet fortified wines include Port, Madeira, Malmsey, Vermouth and Muscat de Beaumes de Venise. Again, the quality of these is only as good as their components: a good base wine and a good quality spirit.
About half way through fermentation (with an alcohol level around 5°) a measure of spirit is added to the tank. This immediately raises the alcohol level. Yeast cannot survive in alcohol levels much above 13/14°, so the fermentation stops and all the unfermented sugar is left in the wine. The resulting wine is both strong and sweet. It is normally transferred to oak barrels at that point for ageing.
Some of the world's great fortified wines include:
Port
Originating from the Douro valley of Portugal, port comes in various styles and quality levels. In particularly good years (usually two or three per decade) a "vintage" year is declared and a vintage port is released. Vintage ports are the aristocrats of the port world and often take around 30 years after release to develop into truly great wines. These should not be confused with Late Bottled Vintage (or LBV) ports: these are ports which have been matured for longer than ordinary ruby or tawny ports in the shippers' cellars, but they are not true vintage ports of a great year. LBVs are ready to drink when they are released.
Madeira
From the island of the same name, Madeira is unique in that after being made- in much the same way as port- it is cooked. The wine is placed in very hot vats (over 50° centigrade) for 90 days. Once again this was an accidentally discovered technique- Madeira wines being shipped in the holds of sailing ships on long voyages were kept in very hot conditions which seemed to caramelize the wines- a flavour that people seemed to enjoy.
Vermouth
This fortified wine (usually manufactured on an industrial scale in the north of Italy) is flavoured with wormwood or other herbs.
Sherry
Sherry, from Jerez in Spain, is perhaps the greatest wine made by the post-fermentation method. In other words, unlike port, the spirit is only added after fermentation is complete. All sherry, therefore, starts life as a completely dry style. Varying amounts of sweet reserve wine are added back in before bottling, according to the style of sherry being made. Another unusual feature of sherry making is the "solera" system of ageing. In the solera 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.
Fortified wines typically range from around 16° to 23° of alcohol- about double the strength of ordinary wines.
Fortified wine tastes and styles
Port comes in many styles and quality levels, but the characteristics are just like those of fine red wines. Vintage ports can be tannic and overpowering when young, but can mature over many years so that the fruitiness and sweetness of the grapes re-emerges.
Sherry also appears under a huge variety of guises. Most sherries are commercial blends, made with consistency in mind: to taste the same year after year in a pleasant but uncomplicated style. There can be a lot more to sherry than that however. Some fine, old, dry sherries develop wonderful walnutty, warm scents and flavours quite unlike any other wine. The finest, true fino sherries are produced when a strange substance called "flor" grows on the top of the open cask as the sherry ages. Flor is a yeast compound, which prevents the sherry from oxidizing and adds subtle complexity to the flavour. Most sherry is made principally from the palomino grape, but look out for sherry made mainly from the Pedro Ximénez grape- these are intensely sweet- wonderful poured neat over good vanilla ice-cream!