Expat wrote:I find it hard to believe that it happens at all. Alcohol would disappear before water. Proof should only ever go down.
Perhaps they're proofing the bottles with new make?
Expat, I find it difficult to contradict you as you're miles ahead of me in this game,
but I direct you to
THIS ARTICLE where it says:
"If humidity is high in the warehouse, then the losses of water are slowed and alcohol is lost preferentially.
This is the typical situation in Scotland, where relative humidity is often 80 – 90%. In drier climates, though, the losses of water can be faster than alcohol,
resulting in an increase in alcohol concentration over time in the spirit maturing in the cask.
"
Does that not make sense?