Aging in the bottle is an ancient technique that benefits the quality. It works in two stages.
The first stage brings harmony between the ultra pure water and the alcohol molecules (cf stew, slow cooking).
During this stage the cocktail becomes smoother, all flavours are perfectly integrated.
In a second stage positive oxidation creates new flavours and a richer, more complex cocktail.
BelRoy's bottle aged cocktails, just like great wines, improve over time.