Quote Originally Posted by Big Mikey View Post
Here's a little tip from the wine world that also works with whiskies. To preserve an open but unfinished bottle of wine, you can purchase canisters of gas that while inert, will displace oxygen. It is the oxygen that causes wines or whiskies to turn. Just shoot a little of the gas into the top of the bottle and recork/seal. This will keep wines for up to a week after opening and I tried it with one of my whiskies and it was still luscious months later.
While I suppose an over-oxidated whisky could get stale or flat, some whiskys do very well with a bit of oxidation. The Balvenie in particular really opens up with exposure to oxygen.

Then again, I've never had a bottle hang around often enough to find out if it will truly go bad.