A wine is fortified itself has undergone an addition of alcohol. In effect an unfortified wine has an alcohol content ranging between 11% and 14%; with the addition of brandy or natural alcohol it passes to a level between 15% and 21%.
The alcohol is added for several reasons: on the one hand to stop the fermentation process, so in order to increase the sugar content; on the other hand, to stabilize the wine giving it a bit of force. Among fortified wines we remember Porto, Madeira and Sherry.
