Blended Scotch is the name for a category of Scotch that is a blend of both malt and grain whiskies from different distilleries. Blended Scotch has been around since the 1850's, and were first made to tame the rough edges of malt whiskies. They have been used as "own brands" by major wine and spirits retailers (Cutty Sark for example was made for the Berry Bros. and Rudd company), and have worldwide appeal.
While Blended Scotch tends to be less expensive than their Single Malt counterparts, some high end blends are priced into the hundreds of dollars per bottle. Blended Scotch makes up more than 90% of the Scotch produced.
Unlike single malt Scotch, which will identify the distillery and region on the label, blended Scotch is typically identified by a brand name. Some examples of well known blended Scotches are: Dewar's, Johnnie Walker, Famous Grouse, Cutty Sark, J&B (like Cutty Sark, originally made for the Justerini and Brooks wine and spirits retailers), and Chivas Regal. Sales of many of these brands have declined in recent years, as consumers drink less but drink more expensively. Many of these brands have released upmarket versions in an attempt to capture a younger following.
The actual blends for these brands can be staggeringly complex. Some contain thirty or forty different single malt whiskies and half a dozen grain whiskies. These Scotches are the height of the Master Blender's craft - there is typically one person whose job it is to maintain consistency from year to year and blending to blending.