Fortification is the adding of alcohol to grape juice which is more or less fermented. Pineau de Charentes, Banyuls, Muscat de Beaumes de Venice and especially port are fortified wines. Discover our fortified wines.

the addition of an ingredient for the purpose of enrichment (as the addition of alcohol to wine or the addition of vitamins to food)

Introducing brandy into the fermenting must to stop the fermentation process. By raising the alcohol level, the yeast are killed, fermentation ends and any unfermented sugars remain in the wine. This is the way ports and several other fortified wines are produced.

the process of adding alcohol to increase content percentage.

Adding alcohol to a wine in order to make it stronger and take on a different character. This process also lessens the possibility of further fermentation, since many wine yeasts can't survive in a higher alcohol environment. Sherries, Madeira, and Ports are examples of fortified wines.

The act of chucking in things like brandy and vodka. Motives for doing this are generally questionable, but can be justified with experienced bluffing, e.g by calling it blending.

Raising the alcohol content (per volume) of a wine by adding a liquor with higher alcohol content.

The process of adding spirit to a wine. If this is done before completion of the alcoholic fermentation, as with Port, the unfermented sugars will cause the wine to be sweeter than would otherwise be the case. Added later, as is the case with Sherry, the wine will remain dry. In all cases the final alcohol content receives an obvious boost. The process is also used in the production of vin doux naturel.

The process of adding distilled spirits to a finished mead to increase its alcohol content, keeping qualities, or flavor.