Port is often used to impart a subtle, caramel-like sweetness to sauces. Genuine port comes from Portugal. Wine makers in other countries have attempted to make port-like wines, some of which are very good, but it is best to use a genuine Portuguese port.
Port is made by adding alcohol or brandy to the wine must before fermentation is completed. This stops the fermentation prematurely and leaves natural grape sugar in the wine. There are four styles of port. Vintage port is made from grapes of a single year and is left in wood casks for a relatively short time before being bottled. Vintage port may last 100 years in the bottle and should have at least ten to fifteen years in the bottle. It is the most expensive of the four types. Late-bottled vintage port (wood port) is left longer in wooden casks, so it matures more quickly. It is lighter in style and less expensive than vintage port. Tawny port is traditionally manufactured by blending ports from different vintages and allowing them to age for many years in oak, which causes the color to turn from deep red to a characteristic brick-like hue. Some less-expensive tawny ports are simple blends of red and white port. Ruby port is a young, blended port. It is the lightest and least expensive.