Its parts are many. The Master Blender selects from between fifteen and fifty different malt whiskies and three or four grain whiskies.

Each is at a different age (by law, they must be at least three years old; some may be twenty-five in even a standard blend), and is chosen from an individual cask

The Age Statement
If the blend bears an age statement, all the whiskies - the grains as well - must have been matured for at least that length of time before they are blended.

He then mixes measured amounts of each of these whiskies - some, the whiskies of Islay, for example, or 'top dressing' Speysides, have the capacity to cover a lot of others, and can dominate unless he's careful. Usually he vats the malts and the grains separately, then blends the two together and leaves them for several months to marry. He must do this for every batch bottled. Consistency of flavour is crucial to the success of blended whisky: if your favourite brand tastes different next time you buy a bottle, you will be disappointed - and may even move to another brand.

Cellos, Violas, Violins & Pianos
Some blenders compare their work to conducting an orchestra. The malts of Islay are heavy and sombre as cellos. Highland malts are violas; Lowlands the discursive violin and grains are like pianos - sometimes fortissimo, sometimes pianissimo.

The Formulae for Blends
The formulae for some blends are a hundred years old, but they are not sacrosanct. Distilleries close and their product is no longer available. Sometimes they choose to withdraw from the blending market and bottle their output as a single (Glenmorangie did this in the early 1980s). From time to time whisky companies alter the composition to suit changing taste. This was recently done, very successfully, by Bell's (a bold step for the U.K. market leader) and the new 8 Years Old is richer and smoother than the previous blend.

"To appreciate the difficulties of blending, the layman should experiment on his own account He may take half a dozen of the finest highland malts, those from the classic distilleries, mix them together and add any proportion he chooses of grain whisky. The result will almost certainly be a blend that is totally unacceptable, one in which all the subtle and distinctive qualities of the different malts hove been entirely lost, The truth is that a good blend requires whiskies of less pronounced character just as much as it needs the classic malts."
(Donold MacKinlay)