The Influence of Cask Maturation on Whisky

There are multiple aspects which influence the flavours in whisky but the casks used in the maturation process play a crucial role.  Distilleries will take meticulous care in their cask selection because at the end of the day, why put so much effort into producing a good quality spirit, if you don’t have high quality casks for maturation?
 
The majority of casks that we see used in whisky production have previously homed another spirit.  For example, ex-bourbon barrels are shipped over from the United States of America and the majority of European sherry casks are imported from the Jerez region in Spain.  Whisky maturation sees no boundaries these days, with an array of casks being used, with the likes of ex madeira, wine, beer and port casks, to name but a few.
 
An excellent example of the astonishing outcome of multiple cask maturations can be seen through the Bowmore 1964 Trilogy Series.  This series boasts three single cask releases, one from an Oloroso, one from Fino sherry and finally one from a Bourbon cask.
 
The Oloroso matured dram oozes sweetness, with the Fino matured coming in a lot drier but delicate, whereas the bourbon matured emanates notes of vanilla and caramel.  A very interesting and tantalising comparison to see how the same neutral spirit can become three such wonderful but distinctive whiskies years down the line.