In order to be called “Scotch,” whisky must be distilled from fermented barley in Scotland, aged there in oak barrels for at least three years and have an alcohol content between 40 per cent and 94.8 per cent. While there are distilleries around the world making whisky in the Scottish style, only whisky made in Scotland can be called “Scotch.”

Despite this simple technical definition, Scotch is a complex spirit that offers thousands of different expressions. All of these expressions come from two types: malt Scotch, which is made solely from malted barley, and grain Scotch, usually made with unmalted grains, although malted grains might also be used. The popular “single malt” is malt Scotch entirely from one distillery. “Blended malt” is a mixture of malt Scotches from more than one distillery and is sometimes referred to as “vatted malt.” “Blended Scotch” is a mixture of malt Scotches and grain Scotch. It is quite rare to find bottlings of pure grain Scotch, though a few exist.

Since Scotch can be aged in used barrels (unlike American whisky, which must use new barrels), each distillery can release many expressions of its whisky. The aging of Scotch for varying lengths of time in American or European oak barrels of differing sizes that previously held things as diverse as bourbon, rye, rum, wine, sherry or port results in an infinite variety of tastes for the Scotch lover.

All Scotches can be further divided according to five officially recognized regions: Campbeltown, Highlands, Islay (pronounced “eye-la”), Lowlands and Speyside. Scotches from each of these regions have certain characteristics associated with them. For example, Islay Scotches are known for their intensely smoky and peaty flavours.

Just as “terroir” affects wine, the regions of Scotland greatly influence the whiskies produced within them. Elevation and wind differences affect the vegetation that grows in the regions which then affect the characteristics of the peat used to dry the malt. Also, water running through the Scottish valleys has highly variable mineral content. And as Scotch ages over years, daily temperature changes cause the oak barrels to expand and contract slightly, causing the cask to literally breath in the air that surrounds it and the whisky inside to take on additional character. For this reason, Scotch aged in distilleries near the ocean tend to take on a salty character.

With thousands of different expressions at prices ranging from under $20 to tens of thousands of dollars per bottle, there is a Scotch for everyone. In next week’s Booze column, we’ll look at Calgary’s vibrant Scotch community. Until then, Sláinte!