Glenfiddich Scotch Single Malt 15 Year Old Solera ReserveThis 15 Year Old expression is created using a technique pioneered by Glenfiddich's Malt Master and its warm, spicy flavors are transformed with the alchemy of the Solera Vat. Aged in European oak sherry casks and new oak casks, the whisky is mellowed in a unique Solera Vat, a large oak tun inspired by the sherry bodegas of Spain and Portugal. Never emptied, and kept half full of whiskies since 1998, the Solera Vat is the secret behind this whisky