4. Maturation
The new-make whisky is then filled into oak casks. The most common types of
oak are American, used in the Bourbon Industry, and Spanish
used for the maturation of sherry. By law the whisky must
mature in casks for 3 years. During maturation the flavour
of the first filled spirit re-emerges and together with the
compounds in the wood enhances the aroma and flavour of the
mature whisky. As each year goes by 2% of the volume is lost
due to evaporation. This is the Angels' Share.
Picture below from the Dunnage Warehouse at Benromach |
Whisky Guide | 
