Decanter
 

What is the primary purpose of a decanter?
How long can you store scotch in one?
How can you ensure the crystal stopper is air tight?

Decanter or Not?
 

I personally would never decant spirits as it serves no real purpose other than AESTHETICS. In my experience, anytime I have tried or tested decanters I have noticed that the stopper lifts VERY EASILY. This is a RED FLAG that indicates it is not a tight seal.

Each time when I open a bottle of whisky, if it is corked, I use the same test; if there is little or no resistence when removing the cork, then I replace the cork with a previous one I have saved from a prior bottle. I save all my corks from prior bottles for this purpose. Sometimes, one may run across a defective screw cap, but it is very rare as screw caps offer a pretty good seal. I also save my screw caps as well. If I cannot find a cork or screw cap that fits, then I transfer to 6 ounce flint bottles ( sterlized prescription bottles that I purchase. ).

By not having a good seal, if one intends to keep an opened bottle for while, then the risk of higher oxidation sets in and secondly more alcohols are released through evaporation before its time and the whisky will take on a whole new complexion.