At what stage in production is Port wine fortified?

Fortification of Port wine occurs during fermentation. This process involves adding a distilled grape spirit, known as aguardente, to the fermenting wine. The purpose of this addition is to raise the alcohol level and stop fermentation prematurely. By doing so, some of the natural sugars from the grapes remain unfermented, which results in the signature sweetness that Port is known for.

The timing of this fortification is crucial because it not only affects the level of sweetness but also the overall profile of the wine, including its flavor, aroma, and body. Fortifying during fermentation allows winemakers to control the level of sweetness in the final product and produces the characteristic style of Port.

The other stages mentioned, such as aging, bottling, and vaporization, do not involve fortification in the way that fermentation does. Aging is where the wine develops complexity and character over time, bottling is simply the final packaging stage, and vaporization does not pertain to the production of Port wine.