Traditionally, liquids were transported in wooden barrels. This is because a big, heavy barrel is still fairly easy to move around.

However, the alcohol in these barrels reacts with the acids and molecules in the wood, and acts as a solvent, picking up flavours and effectively ‘mellowing out’.

Most spirits are aged in American Oak or European oak. Each species will impart a unique flavour, and no two barrels are exactly the same. Ageing is more of an art than a science

Ill hand you over to Simon for a good explanation