First, it would be instructive to take a moment to define the terms. Single cask whisky is a subset of single malt whisky; the bull’s-eye, if you will, in the center of the single malt realm. Every single cask whisky is considered a single malt by virtue of the fact that it’s contents all derive from a single distillery. But a single cask malt is never mixed, married or blended and, as a result, the cask contents are distinct and unique. Sometimes the contents are turned over into a new cask for double wood maturing, but in those instances, the contents are not augmented or mixed with other spirit. What you get after maturing is a spirit that takes on the character of the wood in which it is aged. Even if you were to refill that cask (and many casks are refilled many times), it would not be as active a cask as it had been for the prior fill, since the spirit previously contained in the cask will have stripped some of the character of the wood (Note that one should be cautious to not automatically rule out a whisky aged in a refill or even a third fill cask, as sometimes the wood is quite active and would produce an even more complex or delicious malt in the second or third fill than in the first fill.).
A single malt, by contrast, is a whisky that is produced all within the same distillery, but is mixed, married or blended from among two or more casks.
Why would anyone set out to mix the contents of several casks, you ask? Well, without turning this into a history lesson, it would seem that consumers began at some point to favor predictability and consistency in their whisky. To meet that preference the distilleries began to blend. Over time distillers learned that, by blending, they could isolate and diminish disfavored scents and flavors while simultaneously isolating and bringing forward desirable scents and flavors. Distillers also learned that there would be less waste (i.e. more profit) to be realized from blending because they could utilize more casks once they became more adept at blending out and neutralizing qualities outside their preferred profile. Over time that pattern reinforced itself and was advanced by people who began to specialize in the craft of blending. These people are Master Blenders.
Master Blenders spend most of their time tending to the consistency of their products. While they get to experiment on occasion, their main function is to guard the flavor profile cultivated by a particular distillery (and by each standard expression in the distillery’s range). Over time they have developed different ways to accomplish this. It used to be mostly art and now it has grown largely into science. It used to be that a distillery hand with a good nose and palate could work his way up to Master Blender, as if by apprenticeship. Now many of the distillers have chemistry or other science degrees. These days, blenders can figure out the why and the how behind their craft and some of the mysteries of blending have yielded to the wonders of scientific breakthroughs in the field.
The story behind blending is the story of how the whisky industry that we know got to be the way it is. Blending led to vatting, as markets continued to mature and the masses began looking for huge volumes of consistent whisky. The larger distilleries learned that they could produce those huge volumes of consistent whisky, cheaply, by mixing some single malt blended whisky with a larger portion of inexpensive grain whisky. Consumers liked it enough and mass-produced whisky was born.
Against this backdrop, it was inevitable that enthusiasts would turn their attention to the crafted blends and leave the mass production stuff for the pedestrian drinkers. Single malt whisky came back into vogue and carved out a niche market for consumers seeking the premium whisky experience. But the thirst for super-premium whisky was not quenched with the return to single malt whisky, just as the insatiable search for the perfect dram drives each member of Single Cask Nation.
I submit that single cask whisky is so special because it allows us to get back to the primal whisky experience. In striving to winnow out characteristics outside the blender’s chosen profile, blends purposefully sacrifice some of the natural qualities imparted on the spirit by the wood in which it is aged. Only by returning to single cask whisky can we experience all the wood flavor infused in the spirit. And single cask whisky is rarely chill filtered, so all the natural fats of the whisky remain in suspension within the spirit. When you sample a single cask whisky, all these incredible micro-experiences come into play and meld into an overall sensory experience that is much richer than the blended single malt experience.
As stated previously, there are many excellent single malts out there, which is a testament to the art and science of blending. If you’re like me, though, one decent dram of single cask whisky spoils you forever. From there, it’s hard to go back to the single malts with the same enthusiasm. I hate the thought of being a snob at anything, so I won’t admit to being a single cask snob. Yet I will allow this much: that the single cask experience is a unique sensory blast at relative value when compared to the price points of the better blended single malts.
Finally, to state the case most succinctly, each single cask bottling is entirely unique. Once it’s gone, it is gone forever. With every sip you are reminded that you belong to a limited group of lucky individuals who will be the only humans to ever experience this very spirit. And that’s pretty cool.
L’chaim and Slainte!