Decanting accelerates the breathing process, which increases the wine's aromas from natural fruit and oak, by allowing a few volatile substances to evaporate. Decanting also apparently softens the taste of the tannins that cause harshness and astringency in young wines.
Do you need to decant red wine?
From young wine to old wine, red wine to white wine and even rosés, most types of wine can be decanted. In fact, nearly all wines benefit from decanting for even a few seconds, if only for the aeration. However, young, strong red wines particularly need to be decanted because their tannins are more intense.
How long should you decant red wine?
He recommends decanting a minimum of 30 minutes, but warns that the process of finding a wine's best moment isn't as easy as setting a timer. “In order to enjoy the peak of the wine after you have opened a bottle, you have to [taste] its evolution from the moment you open it.