Scotch is the proper name for whiskey produced in Scotland, although other countries do produce similar grain-based liquors. In Ireland, the same basic product can be called Irish whiskey, while American whiskey is often called bourbon. Most Scotch whiskey is considered blended, which means the end product is a carefully mixed combination of up to 50 separate single malt whiskeys created specifically for blending. Some single malt Scotch whiskeys are sold directly to the public, but most are used as separate ingredients in a skilled blender's palette.
Scotch whiskey is usually made from cereal grains, primarily barley. To make a malted Scotch whiskey, barley grains are first cleaned and soaked in tubs for several days. This soaking causes the barley seeds to germinate, and an enzyme called diatase turns the barley's germ into a soluble starch. A mechanical drying and turning process removes the starchy pulp from the unusable husks. The barley grain is now considered to be malted.
This dried malted grain is then mixed with hot water to form a sugary liquid called wort. This wort is the essential ingredient of a malted Scotch whiskey. The wort is carefully drawn away from the mashing tank, called a mash tun in Scotland. Once the wort has cooled down sufficiently, it is stored in another tank for fermentation. Live yeast is added to the sugary wort, which causes the sugar to be converted into a basic alcohol. After a few days of fermentation, the result is a rather pungent combination of unrefined alcohol and solids called wash. This would be the equivalent of corn mash in American bourbon making.
Scotch whiskeys are actually distilled twice. The wash is heated until the alcohol turns into a vapor. The vapor is led through a series of coiled tubes into a cooling vat, where it becomes a liquid again. This liquid is distilled a second time and the results are collected in oak casks for long-term storage. A true Scotch whiskey must be allowed to age for at least three years from the time of distillation. Some Scotch whiskeys are aged for 15 years or more, which may explain their mellow flavors and significant price tags.
Once the single malt or grain whiskeys have been properly aged, a skilled whiskey blender uses his native understanding of each single malt Scotch whiskey to create a blended Scotch. This process can involve up to 50 separate whiskeys, since individual whiskey sources may or may not complement each other. 95% of all Scotch whiskeys sold in the world are blended, although some say certain single malt Scotch whiskeys are just as worthy of consideration as their blended counterparts.