Port wine is typically a sweet wine that is served after dinner, so it is often called a dessert wine. It is usually sipped because of its intense sweetness and its high concentration of alcohol. The glasses used specifically to serve port wines are generally much smaller than red, white, or sparkling wine glasses because a smaller amount of dessert wine is usually poured. The glasses for port are thought to be best if they have a smaller size than standard wine glasses and a small straight or slightly fluted rim.
Different glass sizes and shapes are used for different wines because of the properties of the individual wines. The types of wine glasses for red wines, for instance, have large bowls and rims to allow more air to hit the wine. Likewise, white wine glasses have smaller bowls and narrower openings to preserve the scent, which helps add to the flavor. Sparkling wines and dry wines, on the other hand, are typically best served in tall glasses, such as champagne flutes, to show the bubbles and concentrate the fragrance. Port wine glasses, however, are often small because this type of wine is considered a dessert drink, and the glasses typically are flared as well, to allow the wine to roll directly onto the tongue.
You can drink port wine out of any type of wine glass you choose, but using proper port wine glasses can enhance both the presentation of the wine and your enjoyment of it. The best wine glasses for almost any vintage are generally clear glasses with no decorations or designs, as the clear glass allows the color of the wine to show through. Wine enthusiasts count appearance as a large part of the enjoyment of drinking wine, so clear glasses are almost always preferred.
Cheap port wine glasses, as long as they are clear and designed in the proper shape, may be just as good as expensive port wine glasses. The choice will depend on your preference and how much you want to spend. When you are serving port, your guests will probably not know the difference between cheap or expensive glasses. People experienced with wine will probably only notice the shape of your port glasses and whether or not they are properly sized.
The best port wine glasses also typically have a rim with a slightly fluted quality. This is said to allow the wine to roll directly onto the tongue. Many port glasses have no fluting but have straight sides instead. The type you choose is really up to your preference, as the most important quality of port wine glasses is typically their much smaller size. If you cannot find glasses designed specifically for port wine, choose the smallest standard wine glasses available and remember to only pour a small amount when serving.