[Update: Aspects of the below article are considerably expanded upon and covered in more detail in our comprehensive feature piece, “The complete guide to oak and whisky maturation” which we suggest you head straight to now and read here. ]
Whisky maturation is a complex process. You’ve doubtless heard or read the oft-accepted mantra that the spirit’s contact with the wood during maturation contributes as much as 60-70% to the whisky’s final flavour.
When it comes to playing around with wood and cask experimentation, few do it better than Glenmorangie. Often credited with the innovation of “finishing” (although Balvenie may beg to differ), Glenmorangie was certainly the first to commercially release a range of whiskies where the whisky was matured primarily in one type of cask, and then given a second period of maturation in a different cask. The “Port Wood” expression was one of my early favourites, having spent 10 years or so in bourbon wood, before being finished for 6-12 months in port pipes.
20 years on, finishing is so common now, it’s passé. For some companies, it also makes economic sense: Not every distillery can afford to invest in expensive sherry casks for a 12 year maturation, but some impressive results can be had by re-racking the whisky in first-fill sherry butts for just 6-12 months. Not surprisingly, the results merge and marry the characteristics of the contributing parent casks, and any number of permutations and possibilities can be trialled. Tired or non-performing whiskies can also be rescued: For some distillers, finishing the spirit in a new or exotic cask can polish or breathe life into whisky that was flat or over-cooked. We won’t name names, but a number of resurrected distilleries have had to do this to rescue tired casks that were inherited when the distillery’s ownership changed hands.