Whiskey (usually spelled whisky in Canada and Scotland) is a spirit produced from fermented grain and aged in wood. A spirit is any alcoholic beverage in which the alcohol content has been increased by distillation. Other spirits include brandy (distilled from wine), rum (distilled from sugarcane juice or molasses), vodka (distilled from grain but not aged), and gin (also distilled from grain and unaged but flavored with juniper berries and other ingredients.)
Undistilled alcoholic beverages such as mead, wine, and beer have been produced since at least 7000 B.C. The process of distillation (heating an alcoholic beverage in order to boil off, collect, and concentrate the alcohol) was first used in China no later than 800 B.C. to produce rice spirits. About the same time in other parts of Asia, distillation was used to produce arrack, a beverage similar to rum, made from rice and sugarcane juice or palm juice. The ancient Arabs, Greeks, and Romans all distilled wine to produce beverages similar to modern brandy. The practice of distillation spread to westetn Europe with the Arabs in the eighth century, particularly in Spain and France.
No one knows where or when the first grain spirits were produced, but they certainly existed in Europe no later than 500 years ago. Some claim that whiskey was invented in Ireland as long as 1,000 years ago and carried to Scotland by monks. In any case, the first written records of Scottish whiskey-making date as far back as 1494. (The word whiskey comes from the Irish Gaelic uisge beatha or the Scottish Gaelic uisge baugh, both meaning “water of life.”)
Spirits were carried to the New World with the earliest European settlers. Rum was distilled in New England in the early 17th century, and distillation also took place in New York as early as 1640. During the early 18th century whiskeymaking became an important industry in the western part of the American colonies, particularly in western Pennsylvania. Farmers found it difficult to store their perishable grains and to transport them to distant eastern cities. It was much simpler to use them to make whiskey, which could be stored for years and more easily transported.
Whiskey played an important part in the early history of the United States, especially during the so-called Whiskey Rebellion of 1794. Farmers in western Pennsylvania refused to pay an unpopular tax on whiskey and attacked federal officers who tried to collect it. After the home of the local tax inspector was burned by a group of 500 armed rebels, President George Washington sent in 13,000 troops to stop the uprising. The rebellion ended without bloodshed, and the power of the federal government was firmly established. Many whiskeymakers moved farther west, into what was then Indian territory, to escape federal authority. They settled in southern Indiana and Kentucky, areas that are still famous for whiskey.
American whiskeymaking reached a peak in 1911, when about 400 million liters were produced, a figure not exceeded until after Prohibition. On November 16, 1920, the Volstead Act became the Eighteenth Amendment to the Constitution of the United States, and no American whiskey was legally made until the amendment was
repealed on December 5, 1933. Production reached another peak in 1951, when about 800 million liters were made. Today about 400 million liters are produced each year.
The earliest devices for distillation consisted of a closed, heated container, a long tube (known as a condenser) through which the alcohol vapor could cool and turn back into a liquid, and a receptacle to catch the alcohol. These were later refined into pot stills, in which alcohol vapor from a heated copper pot was condensed in a helical, water-cooled copper tube called a worm. Pot stills are still often used to make whiskey in Scotland and Ireland and brandy in France. In Scotland in 1826 Robert Stein invented continuous distillation, in which alcohol could be distilled continually rather than batch by batch. This process was improved by the Irishman Aeneas Coffey in 1831 and is still used to make most mass-produced whiskey today.
Whiskey is popular around the world and is made almost everywhere. The United States makes and consumes more whiskey than any other nation, but the most celebrated whiskey is still Scotch whiskey, often just called Scotch.
Whiskey is made from water, yeast, and grain. The water used is often considered the most important factor in making good whiskey. It should be clean, clear, and free
from bad-tasting impurities such as iron. Water that contains carbonates, found in areas that are rich in limestone, is often used in the United States, particularly in Maryland, Pennsylvania, Indiana, and Kentucky. Scottish water is famous for being suited to making fine whiskey, for reasons that are still somewhat mysterious.
Every whiskeymaker keeps a supply of yeast available, grown on barley malt and kept free from bacterial contamination. Some whiskeymakers use several kinds of yeast to control the fermentation process precisely.
The type of grain used varies with the kind of whiskey being made, but all whiskeys contain at least a small amount of malted barley, which is needed to start the fermentation process. Scotch malt whiskey contains only barley. Other whiskeys contain barley in combination with corn, wheat, oats, and/or rye. Corn whiskey must contain at least 80% corn, while Bourbon whiskey and Tennessee whiskey must contain at least 51% corn. Rye whiskey must contain at least 51% rye, and wheat whiskey must contain at least 51% wheat.
Straight whiskeys contain no other ingredients, but blended whiskeys may contain a small amount of additives such as caramel color and sherry.
The Manufacturing Process
Preparing the grain
- 1 Truckloads of grain are shipped directly from farms to the whiskey manufacturer to be stored in silos until needed. The grain is inspected and cleaned to remove all dust and other foreign particles.
- 2 All grains except barley are first ground into meal in a gristmill. The meal is then mixed with water and cooked to break down the cellulose walls that contain starch granules. This can be done in a closed pressure cooker at temperatures of up to 311°F (155°C) or more slowly in an open cooker at 212°F (100°C).
- 3 Instead of being cooked, barley is malted. The first step in malting barley consists of soaking it in water until it is thoroughly saturated. It is then spread out and sprinkled with water for about three weeks, at which time it begins to sprout. During this germination the enzyme amylase is produced, which converts the starch in the barley into sugars. The sprouting is halted by drying the barley and heating it with hot air from a kiln. For Scotch whiskey, the fuel used in the kiln includes peat, a soft, carbon-rich substance formed when plant matter decomposes in water. The peat gives Scotch whiskey a characteristic smoky taste. The malted barley is then ground like other grains.
- 4 Mashing consists of mixing cooked grain with malted barley and warm water. The amylase in the malted barley converts the starch in the other grains into sugars. After several hours the mixture is converted into a turbid, sugar-rich liquid known as mash. (In making Scotch malt whiskey the mixture consists only of malted barley and water. After mashing the mixture is filtered to produce a sugar-rich liquid known as wort.)
- 5 The mash or wort is transferred to a fermentation vessel, usually closed in Scotland and open in the United States. These vessels may be made of wood or stainless steel. Yeast is added to begin fermentation, in which the single-celled yeast organisms convert the sugars in the mash or wort to alcohol. The yeast may be added in the form of new, never-used yeast cells (the sweet mash process) or in the form of a portion of a previous batch of fermentation (the sour mash process.) The sour mash method is more often used because it is effective at room temperature and its low pH (high acidity) promotes yeast growth and inhibits the growth of bacteria. The sweet mash method is more difficult to control, and it must be used at temperatures above 80°F (27°C) to speed up the fermentation and to avoid bacterial contamination. After three or four days, the end product of fermentation is a liquid containing about 10% alcohol known as distiller’s beer in the United States or wash in Scotland.
- 6 Scottish whiskeymakers often distill their wash in traditional copper pot stills. The wash is heated so that most of the alcohol (which boils at 172°F [78°C]) is transformed into vapor but most of the water (which boils at 212°F [100°C]) is not. This vapor is transferred back into liquid alcohol in a water-cooled condenser and collected. Most modern distilleries use a continuous still. This consists of a tall cylindrical column filled with a series of perforated plates. Steam enters the still from the bottom, and distiller’s beer enters from the top. The beer is distilled as it slowly drips through the plates, and the alcohol is condensed back into a liquid. With either method, the product of the initial distillation—known as low wine—is distilled a second time to produce a product known as high wine or new whiskey, which contains about 70% alcohol.
- 7 The temperature of distillation and other factors determine the proportions of water, alcohol, and other substances (called congeners) in the final product. If it contains more than 95% alcohol it will have no flavor because it has no congeners. This product is known as grain neutral spirit and is often used to add alcohol without adding taste during blending. If the final product has too many congeners of the wrong kind it will taste bad. Distillers remove bad-tasting congeners (usually aldehydes, acids, esters, and higher alcohols) in various ways. Some congeners boil at a lower temperature than alcohol and can be boiled off. Some are lighter than alcohol and will float on top, where they can be poured off.
- 8 Tennessee whiskey is unique in that the high wine is filtered through charcoal before it is aged. The charcoal is produced by burnning wood from sugar maples. This filtration removes unwanted congeners and results in a particularly smooth whiskey. Premium Tennessee whiskey may be filtered through charcoal again after it is aged to produce an even smoother product.
- 9 Water is added to the high wine to reduce its alcohol content to about 50% or 60% for American whiskeys and about 65% or higher for Scotch whiskeys. Scotch whiskeys are aged in cool, wet conditions, so they absorb water and become less alcoholic. American whiskeys are aged in warmer, drier conditions so they lose water and become more alcoholic. Whiskey is aged in wooden barrels, usually made from charred white oak. White oak is used because it is one of the few woods that can hold a liquid without leaking but which also allows the water in the whiskey to move back and forth within the pores of the wood, which helps to add flavor. In the United States these barrels are usually new and are only used once. In most other countries it is common to reuse old barrels. New barrels add more flavor than used barrels, resulting in differences in the taste of American and foreign whiskeys. The aging process is a complex one, still not fully understood, but at least three factors are involved. First, the original mixture of water, alcohol, and congeners react with each other over time. Second, these ingredients react with oxygen in the outside air in oxidation reactions. Third, the water absorbs substances from the wood as it moves within it. (Charring the wood makes these substances more soluble in water.) All these factors change the flavor of the whiskey. Whiskey generally takes at least three or four years to mature, and many whiskeys are aged for ten or fifteen years.
- 10 Straight whiskeys and single malt Scotch whiskeys are not blended; that is, they are produced from single batches and are ready to be bottled straight from the barrel. All other whiskeys are blended. Different batches of whiskey are mixed together to produce a better flavor. Often neutral grain spirit is added to lighten the flavor, caramel is added to standardize the color, and a small amount of sherry or port wine is added to help the flavors blend. Blended Scotch whiskey usually consists of several batches of strongly flavored malt whiskeys mixed with less strongly flavored grain whiskeys. A few blends contain only malt whiskeys. Blending is often considered the most difficult and critical process in producing premium Scotch whiskeys. A premium blended Scotch whiskey may contain more than 60 individual malt whiskeys which must be blended in the proper proportions.
- 11 Glass is always used to store mature whiskey because it does not react with it to change the flavor. Modern distilleries use automated machinery to produce as many as 400 bottles of whiskey per minute. The glass bottles move down a conveyor belt as they are cleaned, filled, capped, sealed, labeled, and placed in cardboard boxes. The whiskey is ready to be shipped to liquor stores, bars, and restaurants.
Although the making of good whiskey is still more of an art than an exact science, there are certain basic precautions that all whiskeymakers take to ensure quality. The water used must be taken from an appropriate natural source. It must be filtered so that it is free from organic matter. The grain used must be very clean. It is also passed through screens to eliminate grains that are too small. The yeast is carefully grown to avoid contamination by other microorganisms. The temperature of distillation is monitored with thermometers in the boiling liquid, which are visible through glass windows in the still. During aging, samples of whiskey are evaluated by experienced tasters to determine if it is mature. The blending process is supervised by master blenders to produce a final product with the proper taste.
Very little of the ingredients used in whiskeymaking are wasted.
The portion of the fermented mash which remains after the distillation can be used for animal feed. The charred white oak barrels used only once in the United States are often sold overseas to age foreign whiskeys. The charcoal used to filter Tennessee whiskey can be pressed into charcoal briquets for barbecues.
Where To Learn More
Jackson, Michael. The World Guide to Whisky. Darling Kindersley, 1987.
Grossman, Harold J. and Harriet Lembeck. Grossman’s Guide to Wines, Beers, and Spirits. Charles Scribner’s Sons, 1977.
Lichine, Alexis. Alexis Lachine’s New Encyclopedia of Wines and Spirits. Knopf, 1976.
Asher, Gerald. “Single Malt Scotch Whiskey.” Gourmet, December 1989, pp. 94-99.
DeMarco, Dan and Frank Bechard. “New Weigh Scales Smooth Distillery’s Production, Improve Inventory Control.” Food Engineering, October 1986, pp. 95-96.
Johnson, Julie. “Mysteries of the Malt.” New Scientist, January 26, 1991, pp. 56-59.
Letwin, William. “More Than a Drink.” National Review, April 18, 1994, p. 14+.
— Rose Secrest
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