Fortified wine is wine to which additional alcohol has been added, the most common additive being brandy.
The original reason for fortification was to preserve wines, as the higher alcohol level and additional sweetness help to preserve the wine when supplemental alcohol is added before fermentation finishes, it kills the yeast and leaves residual sugar.
Even though other preservation methods exist, the fortification process survives, as consumers have developed tastes for wines preserved this way. Many different wines styles have developed around the use of fortification in winemaking.
Fortified wines are distinguished from spirits made from wine. While both have increased alcohol content, spirits are the result of a process of distillation, while fortified wines have spirits added to them. Fortified wines generally have an alcohol content between that of wines and spirits.
Fortified wines are legally called dessert wines in the U.S. but are called liqueur wines in Europe.
In the UK they are called fortified wines except where the European Union insists on the use of liqueur wine.
Sherry, one of many fortified wines, is typically made from the Palomino grape and classified into various styles; Fino, Amontillado and Oloroso.
Sherry production utilises a dynamic method of blending and aging the wines, known as the Solera system.
Muscat and Tokay styles are made from the Frontignac variety and Muscadelle variety respectively.
The grapes are allowed to ripen and shrivel on the vines before picking and crushing. The sugar level of the juice is higher than other wines and when the sugar level starts to drop, spirit is added, stopping fermentation and resulting in wines that are very high in sugar.
The fortified juice is stored and matured in oak casks, where evaporation plays an important role in the concentration of flavours and complexity of these wines.