(n.) Scotch, a type of Scottish whisky made from malted barley, must be distilled below 190 proof and aged for three years in oak barrels. Basic production works like this: A low-alcohol product is made from fermenting malted barley, which is then distilled twice in pot stills for a more artisanal bent, or in column stills for industrial production. Variations come from the quality of the barley (which can be imported from elsewhere), water sources, yeast, stills, and, in particular, the type of malting that the barley undergoes.
Though it’s possible to buy malted barley, many houses malt their own, which entails soaking the grain until it sprouts, then drying it out with either hot air or a peat<LINK> fire. Peat is made up of decomposed vegetation and is common in the bogs of Scotland, particularly on the Islay islands. When burned, peat imparts a particularly smoky note to the barley, which correlates to smoky notes in the whisky.
Different areas of production are known for certain styles. Islay scotches tend to have a particularly smoky character. The Speyside region skews fruitier and has more distilleries than any other region. Other areas of production include the Highlands, the Lowlands and Campbelltown, and styles vary widely among individual producers.
Scotch may be made either in a single-malt style, which comes from one particular distillery, or a blended style, which mixes more than two single malts from different distilleries. If made with grains besides malted barley it is labeled “grain whisky,” which can be sold in either single grain or blended styles. Any type of cereal grain is permitted (such as corn, wheat or un-malted barley), though malted barley must also be used.
The popularity of single-malt scotch is a relatively recent phenomenon. Blended whiskies were considered a better bet during the 19th and early-20th centuries, giving rise to the big Johnnie Walker, Chivas Regal and Cutty Sark brands. In 1963, however, William Grant began promoting the Glenfiddich single malt worldwide, which sparked a rise in the perception of quality of single malts, and almost every other distillery has followed suit.
Without a vintage date, scotch must be aged for three years in wooden barrels before being sold. The barrels typically come from used bourbon barrels, which impart notes of vanilla and caramel. Sherry<LINK> and port barrels are used to a lesser extent, and leave notes of fruit, nuts and spice. If a scotch bears a vintage date, it is the youngest vintage used in the bottle.