It is a common misconception that upon removing the cork, all bottles of wine need to be given time to breathe. This is not always the case. Not all wines require aeration. However, different wines require different amounts of time. Many wine sellers have experts that are educated on the wine they are selling so it's best to consult them regarding aeration time.
As soon as you open a bottle of wine, pour a small amount into your glass for a taste test. Wine is subjective in that there is no right or wrong flavor. If the wine is to your liking, then it's time to drink!
For wine that has aged for some time, a decanter is highly recommended. Many people simply open their bottle and let it sit. While adequate, it is not ideal. Decanting is a terrific technique for letting newer wines aerate and removing older wines' sediment. Sediment occurs in wine when pigments and tannins within the wine breakdown, leaving behind a harmless but bitter residue. Not only is sediment displeasing to the mouth, it's displeasing to the eye as well.
When decanting a wine with sediment, it's best to let the bottle stand upright, undisturbed for 24 hours. This allows the sediment to collect at the bottom of the bottle. After this allotted time, slowly pour your wine into a cleaned decanter. Observe the wine as it passes through the neck, stopping your pour upon the first sign of sediment.
The final result of this process leaves a decanter of pure wine and a bottle with some sediment-heavy wine left in it. While the remaining un-decanted wine may not taste the best, it makes a great addition to gravy or red sauces. Many wine enthusiasts pride themselves on their ability to find new and exciting uses for sediment-laden wine.
Proper decanting alters wine for the better, softening its bite and developing aromas and flavors more pleasing to the taste buds. Whether 100-years-old or one day, any bottle of wine will benefit from a decanter!