Originally Posted by p_froes
This is totally untrue. Apart from the fact that according to many experts whisky does change in the bottle, no blend made 25 years ago will contain exactly the same malt and grain whisky as today. Put this one next to a new one and I guarantee they will be very different, and the older one will probably taste nicer.
Whiskey does not age in the bottle like it did in the barrel! Any change would be due to exposure to light or the bottle was opened and partially consumed and the air trapped inside would, over time, have some impact on the freshness of the spirit.