What? Not only a mixture of whiskies from different distilleries, but also a mixture of two different types of whisky: grain and malt. Grain whisky is the distillate of a number of different unmalted cereal grains processed through a continuous still at high strength. It is lighter in character and cheaper to produce than malt whisky, which is made in batches in pot stills from fermented malted barley and is rich and complex in character. The number of different whiskies in each blend various enormously, as does the ratio of grain to malt content.
Where? Scotch blends are collectively dominant globally, but are some very big Irish blends like Bushmills and Jameson. The Japanese blends we get in Europe now are a bit more expensive, but exceptionally well put together.
When? Blending really takes off with the invention and refinement of the continuous still in the 1820s and 1830s. This allowed a very consistent and affordable spirit to be produced, and was adopted with enthusiasm in Scotland and a little slowly in Ireland.
How? Although good blending is an art to be appreciated with respect in a nosing glass, blended whisky is free from some of the snobbery that is attached to single malt. Ice is fine, and the gingers (ale and beer) work really well.
Where To Start? Of the big boys Johnnie Walker Black Label is a remarkably good example of a smoke-led blend, but if you like things crafty the boutique blending of John Glaser at Compass Box is worth your support.