Variables, Consistency, and House Style
When whisky is aged in oak barrels, a number of variables influence the final character of the spirit. A full discussion of these variables is beyond the scope of this article, but they include climate variations, where a barrel ages within its warehouse, and even variables in the quality of the oak used to make the barrels.
Because so many variables influence the character of a barrel of whisky, nearly all whiskies on the market today are made by mixing barrels together to achieve a product that's consistent from one release to the next. A master blender at the distillery tastes through the barrels that are ready for release and mixes them to create a product consistent with the brand's flavor profile. Not every barrel produced at, say, Springbank or Glenmorangie will exactly fit the house style that consumers expect. To achieve that house style, then, requires a blend of whiskies from many barrels.
What Is Single Barrel Scotch
A single-barrel scotch is the product of a single barrel of whisky, unmixed with whisky from other sources. Because the flavor, aroma, color, and other characteristics vary from barrel to barrel, each barrel release is a unique product. Single-barrel releases are therefore inconsistent from one release to the next. Not many of these exist in the scotch universe (they're much more common in American whiskeys), but Balvenie has a couple of them available.
Other Whisky Blends
So we've established that single malts are usually produced by blending whiskies from different barrels produced within a single distillery. What about all these other blends we hear about? There are three types you'll encounter:
• Blended malt scotch whisky: Formerly called vatted malts, these are a blend of single malts from two or more distilleries. Companies such as Compass Box purchase whiskies and blend them to create new products with certain characteristics. Peat Monster, for example, is a Compass Box whisky that emphasizes the rich, smoky flavor of peat.
• Blended grain scotch whisky: A blend of single grains from two or more distilleries. Single grains are usually known for being light and mild, but some distilleries produce exceptional grain whiskies. Compass Box's Hedonism is a fine example of a blended grain scotch.
• Blended scotch whisky: What many consumers think of when they hear the word blend, blended scotches comprise 90% of the scotch category in sales. A blended scotch is a mix of both malt whiskies and grain whiskies, sourced from several different distilleries. Brands include Johnnie Walker, Dewar's, Cutty Sark, J & B, and Chivas Regal.