What is the purpose of decanting wine?
There are two main reasons for decanting wine.
The first is physical—to separate clarified wine from solids that have formed during aging.
The second is the effect of oxidation and evaporation; both affect our perception of flavor, texture, and aroma. Oxidation and evaporation both seem to help dissipate some of the harsher aromatic components in aged wine but can simultaneously make a wine more aromatically pleasing.
Rather than 2-3 hours of decanting, it typically takes months or even years to modify the tannic structure of a wine. A fragile or aged wine should be decanted 30 minutes before serving. Younger wines should be decanted for 1-2 hours before serving. However, you should know your wine before you “air it” because some wines behave differently when decanted compared to others.