III.

Production

All whiskeys are made from grain or malt (sprouted grain), or from both, and water. Certain other substances, such as sherry wine and caramel (burned sugar), may be added to blended whiskey in small amounts. Most whiskeys are light to dark amber in hue; their coloration is derived either from the introduction of caramel or from exposure to the effects of charred wood, or from a combination of both. The quality of the water used is considered crucial to the quality of the whiskey. Therefore, most distilleries have access to spring water that passes up through granite or limestone.

For Scotch the whiskey-making process begins when whole grain is steeped in water to promote germination. For American whiskeys, the process commences with milling and cooking the grain. In both cases the object is to release the starches stored in the endosperm of each seed of grain. These starches then are converted to fermentable sugar by malt: For Scotch, self-generated malt is produced by arresting germination of the barley; for most other whiskeys, malt is added to the basic grain mixture. (In the production of Scotch, the malted grain is dried at this juncture—traditionally, over peat fires from which the characteristic smoky flavor of finished whiskey is derived—and is then lightly milled.) Hot water is then added to the malted grains, and the resultant mash is stirred or otherwise agitated until the sugars present are dissolved. Wort, the liquid thus produced, is strained into fermenting vessels; fermentation is then activated by the introduction of yeast, which converts the sugars to alcohol and the mixture to a crude whiskey, called wash, with a low alcohol content by volume. The wash is then distilled: It passes successively through a heated vaporization still; the resultant vapor is liquefied in water-cooled coils; and both processes are repeated. After distillation, the still-colorless whiskey is deposited in charred wooden (usually oak) barrels and left to mature, mellow, develop color, and purge itself of impurities—a process that may take up to 20 years but most commonly is of 8 years' duration or less. The alcoholic strength of whiskey is measured by a figure known as the proof, representing twice the volume percentage of alcohol. The proof increases as the water content partly evaporates but is reduced before bottling by diluting the whiskey with distilled water. Most whiskey is sold at 80 to 86 percent proof.