The Lincoln County Process is a step used in producing almost all Tennessee whiskeys. The whiskey is filtered through—or steeped in—charcoal chips before going into the casks for aging. The process is named for Lincoln County, Tennessee, which was the location of Jack Daniel's distillery at the time of its establishment, but is no longer used in that county (where the only remaining distilleries are Benjamin Prichard's, which doesn't use the process, and Southern Pride Distillery).
Nearly every distillery creating Tennessee whisky uses maple charcoal filtering, though the actual process for accomplishing this varies by company.
For Jack Daniel's, the charcoal used is created onsite from stacks (ricks) of two-by-two-inch (5 by 5 cm) sugar maple timbers. The timbers are primed with 140 proof (70% ABV) Jack Daniel's and then ignited under large hoods to prevent sparks. Once they reach the char state, the ricks are sprayed with water to prevent complete combustion. The resulting charcoal is then fed through a grinder to produce bean-size pellets that are packed into 10-foot (3.0 m) vats used to filter impurities from the 140 proof whiskey. The whiskey is then reduced with water to 125 proof (62.5%) for aging. The process was taught to Jack Daniel by Nearest Green, the namesake of Uncle Nearest Premium Whiskey.
The George Dickel distillery uses deeper (13-foot [4.0 m]) vats and distills the whisky—the spelling used by Dickel—to 135 proof (67.5%). Dickel chills its whisky to 40 °F (4 °C) before it enters the vats and allows the liquid to fill the vats instead of trickling it through.
Collier and McKeel, made in Nashville, uses a method that pumps the whiskey slowly through 10–13 feet (3–4 m) feet of sugar maple charcoal (instead of using gravity) made from trees cut by local sawmills.
Some producers claim that according to a 1941 Internal Revenue Service ruling issued at the request of Jack Daniel Distillery, the Lincoln County Process is what distinguishes "Tennessee whiskey" from "bourbon". However, not all producers of products labeled as Tennessee whiskey use the process. (Specifically, it is not used in the production of Benjamin Prichard's Tennessee Whiskey.)
The term "Tennessee whiskey" does not actually have a legal definition in the U.S. Federal regulations that define the Standards of Identity for Distilled Spirits. The only legal definition of Tennessee whiskey in U.S. federally recognized legislation is the North American Free Trade Agreement (NAFTA), which states only that Tennessee whiskey is "a straight Bourbon Whiskey authorized to be produced only in the State of Tennessee". This definition is also recognized in the law of Canada, which states that Tennessee whiskey must be "a straight Bourbon Whiskey produced in the State of Tennessee". None of these regulations requires the use of the Lincoln County filtering process (or any other filtering process).
On May 13, 2013, the governor of Tennessee signed House Bill 1084, requiring maple charcoal filtering to be used for products produced in the state labeling themselves as "Tennessee whiskey" (with a particular exception tailored to exempt Benjamin Prichard's) and including the existing requirements for bourbon. As federal law requires statements of origin on labels to be accurate, the Tennessee law effectively gives a firm definition to Tennessee whiskey.
- "Distillery Visit: George Dickel". Alcademics. June 8, 2012.
- "Jack Daniels". Megafactories. Season 4. March 11, 2011.
- Risen, Clay (June 25, 2016). "Jack Daniel's Embraces a Hidden Ingredient: Help From a Slave". The New York Times. Retrieved July 14, 2018.
- "The Renaissance Of Nelson's Greenbrier". The Whiskey Reviewer. Retrieved July 14, 2018.
- "Collier and McKeel Tennessee Whiskey". March 7, 2013. Archived from the original on March 7, 2013.
- "Collier and McKeel Tennessee Whiskey". Thirsty South. November 17, 2011. Retrieved July 14, 2018.
- Waymack, Mark H.; Harris, James (August 1995). The Book of Classic American Whiskeys. pp. 175–177. ISBN 9780812693065. OL 784496M.
- "Whiskey Facts". Prichard's Distillery. Archived from the original on July 15, 2011.
- "Standards of Identity for Distilled Spirits, Title 27 Code of Federal Regulations, Pt. 5.22" (PDF). Retrieved October 17, 2008.
- "North American Free Trade Agreement Annex 313: Distinctive products". sice.oas.org. Retrieved November 29, 2023.
- "Canada Food and Drug regulations, C.R.C. C.870, provision B.02.022.1". Archived from the original on January 6, 2011. Retrieved June 10, 2011.
- Zandona, Eric (September 16, 2013). "Tennessee Whiskey Gets a Legal Definition". EZdrinking. Archived from the original on January 7, 2014. Retrieved January 11, 2014.
- "Public Chapter No. 341" (PDF). State of Tennessee. Retrieved March 19, 2014.
- Esterl, Mike (March 18, 2014). "Jack Daniels Faces Whiskey Rebellion". The Wall Street Journal. Archived from the original on March 19, 2014. Retrieved March 18, 2014.
- "Enforcement Policy Statement on U.S. Origin Claims". Federal Trade Commission. April 24, 2014. Retrieved July 15, 2018.