About Fortified wine[]
Wikipedia Article About Fortified wine on Wikipedia
A fortified wine is a wine to which additional alcohol has been added, most commonly in the form of brandy (a spirit distilled from wine).
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.