Decanters have traditionally been used to serve certain types of spirits, including whiskey, cognac and brandy. Decanters are also used to aerate, decant and serve wine.
Decanters used to serve liquors are traditionally square and made from crystal or cut glass. They typically have stoppers. Decanters used for wine are usually rounded and have spouts. Both types of decanters come in a variety of shapes and sizes.
The use of decanters for serving liquors is primarily for presentation. Some feel that a decanter makes a more sophisticated presentation. It may be used to disguise inexpensive liquors.
Decanters for wines serve a more practical purpose. They are used to separate the wine from any sediment that may be in the original bottle. They also aerate the wine, adding a small amount of oxygen to help release the flavor of the wine.