Glenmorangie 1977 21 Year Old

A rare vintage Glenmorangie, distilled in 1977 and bottled in 2000.

This is from the dates this should be a 23 year old, although the box clearly states its a 21 year old. The official explination as is follows  vatted from casks (distillation between April and June 1977) in 1998. Between this time and the bottling in 2003, there were several bottlings. A proportion of the whisky in the other bottlings had been stored in vat and a proportion returned to oak casks between 1998 and 2003. As vats are not made of oak, the time in vat cannot be added onto the maturation age of the whisky i.e. a proportion of the whisky can still only be called 21 years. Hence the whisky must still be called 21 years old, despite some of the whisky in its composition maturing for longer in oak casks (up to 23 years old).