Opened bottle gone flat

Taking a moment's reflection, Curt Gomer mused: | | I ran across Bunnahabhain for the first time on a trip to Aberdeen this | spring, enjoyed it and brought a bottle home from the Duty Free. | It remained a very enjoyable bottle of whisky for a month or so, but then | seems to have gone flat. | I usually rotate between 4 or 5 bottles here at home, so a bottle often | lasts me few months. I have not detected a change in the whiskey so soon | after the bottle was uncorked before. | Was this just a fluke, or is it common with some whiskys? | Other than the obvious solution of drinking faster, is there any way that | might preserve the "freshness"?

I noticed this once with a bottle of Talisker. Hadn't happened on previous bottles, and hasn't on subsequent either. I suspected then that the cork just hadn't held a good seal. Though, I don't really know what the problem was.

then seems to have gone flat.

I think there are whiskies that are prone to dulling more quickly than others. They need their spirity freshness to still be assertive, and to keep the flavors dancing. 'White winey' whiskies like Glengoyne or Cardhu, in my experience, don't do well in an open bottle, and I think that is generally true of lighter style whiskies. They don't have the mountains and rivers of flavor (and naturally long finish) that allow them to stay interesting--and even sometimes be more enjoyable--once exposure to air starts to tame them. They start to get very tired and even a little musty, and simply don't have the zest to still make their flavor burst on the palate. I don't know about Bunnahabhain--and now that I immediately decant my full bottles into 4 airline wine-sized bottles, and drink the 'open' ones before long, I might not have a chance to find out!