Decanting is only necessary for older wines and ports that contain sediment. The sediment may add bitterness to the wine, but it may also be removed for aesthetic reasons. Decanting improves the flavour of many old red wines by providing the wine with a chance to "breathe", but the wine should be consumed soon after because it will begin to diminish. In addition, young wines often benefit from the aeration and rest (about an hour) that decanting provides.

Until the wine is ready to be decanted, let it rest upright so the sediment will sink to the bottom. Then slowly pour the wine into the decanter, keeping the bottle at an angle. A cheesecloth or other sort of filter can be used to drain sediment, but this is often done out of your guests sight

The classic decanting method involves holding a candle (or other small light) behind the bottleneck so you can see and stop any travelling sediment from entering the glass.