By definition, the term decant means to pour from one container into another. However, the reasoning behind using a decanter is so complicated that many sommeliers consider it an art in and of itself. “The best way to explain why some wines are decanted and some are not revolves around tannins,” says bar manager for Detroit’s SheWolf, Nelson Kazan.
The biomolecules are found in the skin, seeds, and stems of grapes, and are often responsible for producing the drying mouthfeel that comes from a sip of wine. “Those tannins need to breathe” he says. The oxygen also helps volatize the esters — the compounds that give a wine its fruity smell — and thereby unlocks flavor as well as aroma compounds that are not quite as discernible when the wine is consumed straight from the bottle.
Calibrating the ideal duration of time a wine should be out is something best left to the wine specialists (it can range anywhere between a period of several hours to even overnight). For at-home wine drinkers, Kazan says a good rule of thumb is 30 minutes of decanting. That should be just enough time to break down some of the reductive aromas and ultimately enhance the flavors.