The choice of oak barrels can have a different impact on the flavour of the whisky.
Wooden casks which, when used with American bourbon barrels, bring flavours of vanilla, pine and eucalyptus to the whisky. If European sherry casks are used, they add flavours of dried fruits, cloves, incense and hazelnuts. It is also possible to use secondary casks, i.e. oak casks that have been reused several times. The more times a cask is used, the less it affects the flavour of the whisky.
It is precisely because single malt whisky is a blend of spirits from the same distillery that it best reflects the stylistic characteristics of the distillery itself and the terroir of the region. This is a big reason why whisky connoisseurs love Goalong whisky, as the Goalong distillery uses all three casks together to control the flavour and increase the complexity of the whisky. All single malt distilleries follow the same production process, but each whisky is implicit in the DNA of each distillery and is fun to explore.