Port wine is a fortified wine produced in the Douro Valley of Portugal. It is made primarily from specific grape varieties, including Touriga Nacional and Tinta Roriz. The fermentation process is stopped by adding grape spirit, which increases the alcohol content and preserves some of the natural sugars, resulting in a sweet flavor. There are several styles of Port wine, including Ruby, Tawny, and Vintage. Each style varies in taste, color, and aging process. Ruby Port is known for its rich, fruity flavor, while Tawny Port has a nuttier profile due to longer aging in wooden casks.