Spirity at the end?

[ScotchPalate]

My brother recently polished off a bottle of Glenfiddich 15 SOlera. He said the bottom of the bottle seemed more spirity than previous drams. I know it's pretty common for character to change when there is more air in the bottle. Is it common for the bottom of the bottle to be spirity?

[atoto]

I had similar experiences with both Balvenie 21 Double Port Wood and Clynlish 14. Both bottles had lingered in my whisky cabinet (opened and at about 25% full) for about 3 months. The freshly opened bottles were totally better in all tasting respects.