Blended whiskies are produced by mixing whiskies that have been produced by different distilleries or from different grains.
Blending whisky allows brands to purchase barrels that have been distilled and aged by different distillers to produce their desired expressions without having to go to the trouble of producing all their own liquid. This can often shortcut an increase in production volume for a brand if their products are in demand, or help them reduce costs.
Huge volumes of blended whisky are sold every year, with popular producers such as Johnnie Walker, Chivas Regal and Jameson contributing to this demand.