How Port is Made

Port, sherry, dessert wines, after-dinner wines all have one thing in common... they have been “fortified.” Fortifying is the process of adding brandy spirits to the fermenting must, creating a very special wine.

The grapes that are used to make port are harvested much the same way as table wine grapes, although often they are allowed to ripen on the vine a bit longer to concentrate the natural grape sugars.

After harvest, the grapes are crushed and pressed, and fermentation is initiated, typically in open fermenters, also much like most table wines.

The similarity with table wines ends when, about halfway through the fermentation process (when the natural grape sugars reach about 9-10%), a high-proof grape spirit (brandy) is added to the fermenting must. By Law, the spirit has to be grape based and distilled to approximately 190 proof – almost pure alcohol.

This brandy spirit halts the fermentation process by killing the yeasts that fuel fermentation. The wine is then racked off into barrels for aging and future blending.

The sweetness one tastes in a fortified wine is the natural grape sugar that has not been fully fermented into alcohol. The higher alcohol in fortified wine is a combination of the alcohol created by the beginning fermentation (around 5-6%), and the brandy spirit added to stop the fermentation process (around 13-14%). Most ports have a total of 18 -21% alcohol, and 8-12% residual sugar.

Sherry typically has the same alcohol level as port, but can range from sweet (cream sherry) to dry. After-dinner wines are unique, proprietary blends of different fortified wines.