Fortification is process that involves addition of grape spirits to still wine to increase the total percent of alcohol level. This procedure is important part of making a sweet and fortified wines like Port, Madeira and Marsala, where the grape spirits is added into the wine before fermentation is finished, leaving a high percentage of residual sugar. The timing and volume of the grape spirit is critical to achieve the final desired alcoholic strength and sugar concentration. Fortification can be used also to find the perfect tasting spot after dealcoholization of the wine.

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