Unlike wine, an unopened bottle of whiskey does not get better the longer it sits on your shelf. It can sit there for years, even decades, as long as it’s stored in the right environment, particularly the right temperature (room temperature, around 55 to 75 degrees Fahrenheit). An opened bottle of whiskey, however, is another story. Like wine, whiskey starts to change and degrade the minute it’s been opened and that first glass has been poured — it just takes a lot longer to happen.
Once the seal on a bottle of whiskey has been broken, exposure to light, temperature fluctuations, oxygen, and even the position of the bottle can impact how quickly or slowly the whiskey goes from good to not so good. Initially, say a few months in, many may feel the whiskey has actually improved after opening, and it’s generally felt that regardless of how and where you store a bottle, most are good for at least two years after they’ve been opened. But if you want to make your opened bottle of whiskey last five years or longer, there are a couple of things you need to do.
The first step is storing your bottle in a cool, dark place that is temperature-controlled and limits the liquid’s exposure to light. If the bottle came in a canister, don’t throw it away, but use it as another layer of protection. The second step is to store the bottle not on its side, as you would with wine, but right-side up. That’s because the alcohol content in whiskey is much higher than it is in wine, and that higher proof can allow the liquid to eat away at the closure, thereby ruining the seal and exposing the liquid to oxidation.