If first-fill sherry and Bourbon casks are the stars of the Scotch whisky world, then refill casks are the equivalent of those actors and actresses you see in television dramas and vaguely recognise, but can never quite put a name to. However, as in the world of thespians, for every headline-making, red carpet-walking ‘celeb’ a hundred journeymen are quietly plying their trade and making vital contributions to the profession.
So first of all, just what is a ‘refill’ cask? In terms of Scotch whisky it as a cask which has already experienced one fill of whisky after its initial fill of
sherry, Bourbon or anything else legally allowable for that matter. Somewhat confusingly, then, a second-fill cask has actually been filled three times, but only twice with Scotch whisky.
Sandy Hyslop is Ballantine’s master blender for Chivas Brothers, and he declares: “Refill casks are certainly not to be looked down on. They are a vital tool for the blender. Refill casks are very, very important to our company, particularly when it comes to blending. They give me extra complexity, I can temper oak effects by their use and they help to provide continuity in older blends.
“Reﬁll casks are certainly not to be looked down on. They are a vital tool for the blender”
“If there are lots of first fill casks in your blend it will bring big flavours. We are talking about blended and single malt Scotch whisky, really. For example, with The Glenlivet 12 Years Old, I don’t want the influence of casks to overpower the distillery character, so there will be a proportion of second and even third fill casks in the recipe. The Glenlivet 12 recipe is almost as complex as that of a blend!”
All casks have limited life spans, but that span is partly determined by the number of fills and the duration of those fills. For example, a second-fill cask which has been used to mature a single malt whisky for 25 years will theoretically have more to contribute to any future contents than a cask of similar age when has been filled three times with eight year old whisky.
The precise nature of the cask’s previous contents is also highly significant, since unless the intention was to produce some special effect, a cask that had previously held a bold Islay malt would not subsequently be employed to mature anything more delicate.
You might imagine that refill casks, whether ex-sherry or ex-Bourbon, would behave in a similar manner, but Hyslop is adamant that this is not the case. “With sherry casks you get a much different effect between first and second fill than you do with Bourbon casks,” he declares. “The sherry flavours come out much more first time around and you need to manage the sherry cask inventory very carefully for things like Aberlour 10 Years Old.
“Sometimes even a second fill sherry cask won’t quite give that rich ‘Christmas cake’ character you’re looking for. I’m always more confident what I’m going to get with second or third-fill Bourbon casks. When a cask has previously been filled with Bourbon, there’s just a slight dissipation of the soft vanilla through future fills.”
Hyslop notes: “For Chivas, as a general rule, the third fill for casks will be grain spirit, as you still need the casks to have maturation potential for grain. Then they will go for garden tubs or oak chips.”