One of the challenges for the so-called new world whisky producing countries is to find the balance or sweet spot with their maturation programs whilst juggling the many forces, demands, and financial factors at play for start-up operations. For new distilleries wanting to bring aged whisky to market sooner and bring in much-needed cash flow, there is temptation and a growing tendency to adopt small-cask maturation in active casks to supposedly fast-track the process. However, as many distilleries in Australia have found to their detriment, aging spirit in 20L or 50L casks for just over two years in ex-wine casks might produce a dark whisky that initially seems ready to some drinkers, but the reality is that only two of the three maturation processes discussed above have partially occurred: The additive and interactive processes have occurred to some extent, but there simply hasn’t been sufficient time for the subtractive process to fully play out. The result is often hot and dry whisky that is over-oaked yet under-matured. The situation is exacerbated at distilleries who insist on using ex-wine casks that have only been toasted, rather than heavily charred, meaning that their casks are less capable of removing (subtracting!) the volatiles and other aggressive compounds that maturation seeks to address. (Hence leading to whisky that is described as “hot”, regardless of the actual ABV percentage.)
Fans of peated whiskies should also be aware that peatiness decreases over time. The phenol levels in the spirit reduce with years in the wood (there’s that subtractive process again!) and so those wanting to experience the real “smoke bombs” should be seeking younger whiskies and not necessarily older releases.
Oak and whisky maturation - trees in the forest
Oak species
It’s no accident that oak is used for making barrels. Coopers have been using it since the middle ages. As natural timbers go, it’s strong, durable, and well suited to storing liquids. Coopers could certainly make barrels and casks out of different species of timber but in both the American and Scotch whisk(e)y industries, oak must be used by law.
When the current single malt boom had its genesis in the early 1990’s, the situation in the Scotch whisky industry – and thus the lore that was written in the books of that era – was pretty much that whisky was matured in either American oak casks (quercus alba) that previously held bourbon, or European oak casks (quercus robur) that previously held sherry. As a gross generalisation, that remains a not-unreasonable statement, but it conveniently ignores a few details, and certainly overlooks some current practices.