There's an old saying in the wine industry: "There are no great wines, only great bottles." Once a wine has been bottled, there are a number of things that can change, transform, and go wrong that can ultimately influence how the liquid tastes when the bottle is opened. How was the bottle stored? Where was it stored? For how long? Basically, as the statement implies, when you're drinking a bottle of wine (especially an older one) you can't simply depend on the vintage or the name of the producer, or even the reputation of the wine itself; the ultimate flavor can still be a crapshoot because of all these outside variables.
It's not uncommon while working the sales floor to hear a customer say something like, "I don't like _______ wine because I had a bottle one time that tasted terrible." However, like we just discussed, there are a number of things that could have affected that wine that had absolutely nothing to do with the wine or the style of winemaking. It may have been a great wine, but the cork happened to have been infected with bacteria. The bottle may have been left in the sun too long. Who knows? My point is this: it's not a good idea to form conclusions about a particular producer based on a small sample of experiences. This goes for wine, but it also goes for single malt whisky.
There's no distillery in Scotland that hasn't produced a bad barrel of whisky, it's just that those barrels don't always make it to the market. Because of the amount of tasting we do and the access we have to samples, I've probably tasted more than 1,000 casks of single malt whisky over the last five years, and within that experience were plenty of bad Macallans, terrible Clynelishs, and stale Glendronachs; despite the fact that all of these distilleries are known for their consistent quality. It's because a single cask of whisky can vary so wildly in its flavor that producers blend large quantities of barrels together, using the qualities of the "good" whiskies to mask the flaws or off-putting flavors of the "bad" ones. Boring barrels usually go into blends, while those that can function as a solo act are carefully selected.
So, for example, when you taste a bottle of Talisker 18 (a pretty good bottle of Scotch), you're actually tasting both great whisky and subpar whisky together; a marriage of casks balancing out into one consistent flavor. When you taste a single barrel selection, however, the quality control is dependent upon the person bottling the whisky, not the distillery itself. It's for this reason that many producers do not like independent bottlings by labels such as Signatory or Cadenhead; not because they're competing against their own distillery names (like Diageo's Mortlach vs. Signatory's Mortlach or Edrington's Highland Park vs. Cadenhead's Highland Park), but rather because they cannot control the quality level. Therefore, a customer might form an association about a rogue bottling of Highland Park that has nothing to do with Edrington's product. This person may assume that, because it was distilled at Highland Park, that all Highland Park will taste that way, yet the whisky they tasted was really just an odd single cask. That must be incredibly frustrating for some of these companies who are trying to control the reputation of their brands.
Because an independent bottler can legally use the distillery name, many consumers are easily confused between single cask releases by third-party bottlers and distillery-direct expressions. More importantly, they don't realize that one is a raw bottling, and the other a carefully-crafted marriage. Therefore, when I hear someone say, "David, I loved your ________ cask that I bought last year. Do you have any other whiskies by that distillery?" I get a bit nervous. One of the most beloved barrels we've sold in the last few years was a 22 year old sherry cask of Mortlach; a decadent, meaty, first-fill sherry delight. However, the 25 year old Mortlach we currently have in stock tastes nothing like it, whatsoever. You could line up twenty barrels of Mortlach, of various ages and from various types of casks, that may or may not have been used multiple times, and not find any continuity between the whiskies; despite the fact they were all made at the same place.
Like I mentioned before concerning a bottle of wine, there are so many factors that can influence the whisky after it's been distilled. What type of cask was it aged in? For how long? Where was it aged? Who bottled it? It's for that reason that I caution our customers about forming summations about distilleries based on their limited single barrel experiences. There are obviously certain characteristics like peat smoke that will cross over between the distillery expressions and the various single barrel releases, but quality is something that doesn't always begin with the distillate. I've had great single barrels of Glen Scotia and terrible single barrels of Port Ellen. I've even tasted some fairly drinkable casks of Loch Lomand, while spitting out bitter, over-aged samples of Brora in disgust.
When it comes to single barrel malt whisky, it's important to direct our judgement towards the barrel as well as the distillery.