No aging in the bottle?

[Mike B]

I've read (on this forum I think) that whisky does not age once it's bottled. Assuming that's true, can anyone explain why the aging process stops once it is bottled?

And also, what about after it is opened and then stored? Any aging take place then?

[blenderm]

For whisky to age there must be 3 elements working together, air, wood and, of course, whisky. Once it's in the bottle there's no air or wood so maturation stops. Again once the bottle is opened there's no aging as there's no wood for it to interact with.

[Mike B]

Hmmm, now that is interesting. Obviously, the wood plays an important and critical role, likely the type and quality of wood as well. It must be some sort of chemical interaction by the sounds of it.

[blenderm]

There have been scientific studies for the past 20 years or so on maturation and what happens in the casks and, although they've found out a lot, they're still researching it. As far as wood it must, by law, be oak but there are huge differences in the types of oak that's used. Not just for flavour pickup but in the porosity of the wood for evaporation in the "angels" share, e.g. French oak, as used for cognac, has a far tighter grain that American White Oak which means that French oak normally doesn't have the same amount of evaporation as white oak.
Quality of the whisky maturation does, to a great extent, depend on how many times the cask is used. It's best to imagine that the wood is a reservoir of flavours and each time the cask is filled and takes flavour there's less left in the reservoir for the next filling, and once it's taken it can't be put back.