Why is there vapour in whiskey bottle where the not even heated up?

The vapour in a whiskey bottle is caused by the evaporation of alcohol from the whiskey. Alcohol has a lower boiling point than water, so it evaporates more easily at room temperature. This is why you can see vapour in the bottle even if it has not been heated up.

The amount of vapour in a bottle of whiskey can vary depending on several factors, including the temperature of the room, the type of whiskey, and the amount of alcohol in the whiskey. Higher-proof whiskeys will have more vapour than lower-proof whiskeys.

The vapour in a whiskey bottle can also contribute to the flavour of the whiskey. When you take a sip of whiskey, the vapour will enter your nose and add to the overall sensory experience.

So, the next time you see vapour in a bottle of whiskey, don't be alarmed. It's just a natural part of the aging process and can contribute to the flavour of the whiskey.