Rye whiskey can refer to two different, but related, types of whiskey:
- American rye whiskey, which is similar to bourbon whiskey, but must be distilled from at least 51 percent rye grain
- Canadian whisky, which is often referred to as (and often labelled as) rye whisky for historical reasons, although it may or may not actually include any rye grain in its production process.
American rye whiskey
In the United States, rye whiskey is, by law, made from a mash of at least 51 percent rye. (The other ingredients in the mash are usually corn and malted barley.) It is distilled to no more than 160 U.S. proof (80% abv) and aged in charred, new oak barrels. The whiskey must be put in the barrels at no more than 125 proof (62.5% abv). Rye whiskey that has been aged for at least two years and has not been blended with other spirits may be further designated as straight, as in "straight rye whiskey".
Rye whiskey was historically the prevalent whiskey in the northeastern states, especially Pennsylvania and Maryland. Pittsburgh, Pennsylvania, was the center of rye whiskey production in the late 1700s and early 1800s. By 1808, Allegheny County, Pennsylvania farmers were selling one half barrel for each man, woman and child in the country. By the 1880s, Joseph F. Sinnott's distillery, Moore and Sinnott, located in Monongahela, Pennsylvania, was the single largest producer of rye whiskey, with a capacity of 30,000 barrels a year.
Rye whiskey largely disappeared after Prohibition. A few brands, such as Old Overholt, survived, although by the late 1960s former Pennsylvania brands like Old Overholt were being distilled mostly in Kentucky.
In the early 21st century, an expanding number of brands are produced by Campari Group (Wild Turkey Rye), Diageo (George Dickel Rye and Bulleit Rye), Heaven Hill (Pikesville Rye and Rittenhouse Rye), Beam Suntory (Old Overholt and Jim Beam Rye), The Sazerac Company (Col. E. H. Taylor, Sazerac Rye, and Thomas H. Handy), and various smaller companies. A particularly large producer is MGP of Indiana (formerly known as Lawrenceburg Distillers Indiana), which is a distiller for many brands that are marketed by others (including some of the large companies previously listed).
Rye whiskey has been undergoing a small but growing revival in the United States. Since the beginning of the 21st century, more producers have been experimenting with rye whiskey, and several now market aged rye whiskey. For example, Brown-Forman began production of a Jack Daniel's rye whiskey and released unaged and lightly aged versions as limited editions. A reconstructed distillery at Mount Vernon (the estate of George Washington) sells a rye that is similar to the whiskey Washington made. At its peak, Washington's original distillery was among the largest producers of rye whiskey in the United States, averaging 11,000 gallons per year. 
Differences between rye and bourbon
Rye grain is known for imparting what many call a spicy or fruity flavor to the whiskey. Bourbon, distilled from at least 51% corn, is noticeably sweeter and tends to be more full-bodied than rye. As bourbon gained popularity beyond the southern United States, bartenders increasingly substituted it for rye in cocktails such as the whiskey sour, Manhattan, and Old Fashioned, which were originally made with rye. All other things being equal, the character of the cocktail will be drier (i.e., less sweet) with rye.
Canadian rye whisky
Canadian whisky is often referred to as "rye whisky" because historically much of the content was from rye. There is no requirement for rye to be used to make Canadian whisky, and the labels "Canadian whisky", "Canadian rye whisky" and "Rye whisky" are all legally permitted, regardless of the actual composition, provided the whiskies "possess the aroma, taste and character generally attributed to Canadian whisky".
In modern practice, most Canadian whiskies are blended to achieve this character, primarily consisting of a high-proof base whisky typically made from corn or wheat and aged in used barrels combined with a small amount of flavoring whisky made from a rye mash and distilled to a lower proof. In some cases, the corn-to-rye ratio may be as high as 9:1. Most contemporary Canadian whiskies contain only a fraction of rye, with the exception of a few brands, such as Alberta Premium and Canadian Club Chairman's Select, which are made from 100% rye mash.
Canadian whisky must be aged in wooden barrels that are not larger than 700 litres, 150 imp gal, 180 US gal for at least 3 years, and the barrels do not have to be new oak or charred. This requirement differs from regulations for U.S. blended whiskey, in which the bulk base spirits are not required to be aged.
- "Standards of Identity for Distilled Spirits". U.S. Government Printing Office. Retrieved 2013-04-12.
- Toland, Bill (May 23, 2007). "Rye is Popular Again". Pittsburgh Post Gazette. Retrieved 2013-12-27.
- "Whiskey Resurrection: A Look at Local Distillers, and How They are Faring in Repeal's 4th Year". The Bulletin Index. September 16, 1937.
- New York Illustrated. New York: AF Parsons Publishing Co. 1894. p. 250. Retrieved 18 April 2018.
- Hopkins, Kate (2009). 99 Drams of Whiskey: The Accidental Hedonist's Quest for the Perfect Shot and the History of the Drink. New York: St. Martin's Press. p. 196.
- "American Whiskey & How It Got to Be This Way". EllenJaye.com. Retrieved 2016-09-04.
- Felten, Eric (July 28, 2014). "Your 'Craft' Rye Whiskey Is Probably From a Factory Distillery in Indiana". The Daily Beast. Retrieved July 23, 2016.
- Cowdery, Charles A. (October 26, 2012). "George Dickel Gives a Different Taste to LDI Rye". The Chuck Cowdery Blog. Retrieved May 19, 2019.
- "Rye's Revival". Wine Spectator. July 31, 2008. Retrieved 2013-04-12.
- "Mount Vernon Distillery". mountvernon.org. Retrieved January 22, 2018.
- See, for example: Wondrich, David (2007). Imbibe!: From Absinthe Cocktail to Whiskey Smash, a Salute in Stories and Drinks to "Professor" Jerry Thomas, Pioneer of the American Bar. Perigee Books. ISBN 978-0-399-53287-0.) At page 241 Wondrich states, in giving the recipe for a Manhattan, that "[a]ll things being equal, a 100-proof rye will make the best Manhattan..."
- "Canadian Food and Drug Regulations (C.R.C., c. 870) - Canadian Whisky, Canadian Rye Whisky or Rye Whisky (B.02.020)". Laws.justice.gc.ca. Archived from the original on 2012-07-09. Retrieved 2013-04-12.
- "Rye: Situation and Outlook". Agriculture and Agri-Food Canada Bi-Weekly Bulletin, AAFC No. 2081/E. Agriculture and Agri-Food Canada. 2006-06-02. ISSN 1494-1805. Retrieved 2013-04-12 – via agr.gc.ca. Italic or bold markup not allowed in: