Lincoln County Process

The Lincoln County Process is a process used in making some Tennessee whiskeys such as Jack Daniel's and George Dickel. The whiskey is filtered through a column of charcoal chips before going into the casks for aging. The process is named for Lincoln County, Tennessee, which was the location of Daniel's distillery at the time of its establishment; subsequent redrawing of county lines means that neither distillery currently using the process is located in the county for which the process is named.

The charcoal used by Jack Daniel's is created on site, from stacks of two by two inch sugar maple timbers called "ricks." They are primed with 140 proof Jack Daniel's, and then ignited under massive hoods that help prevent sparks. Once they have reached the char state, the ricks are sprayed with water to prevent complete combustion. The resulting charcoal is then run through a grinder to reduce it to consistent bean-size pellets. These are then packed into 10-foot (3.0 m) vats, where they are used to filter impurities from the 140 proof whiskey, after which the whiskey is reduced with water to 125 proof for aging.

The George Dickel distillery uses shallower vats, chills its whiskey before it enters the vats, and allows the whiskey to fill the vats instead of just trickling it through. The distillery claims that these differences yield a better filtering process.

Some producers claim that according to a 1941 Internal Revenue Service ruling issued at the request of the Jack Daniel's distillery, the Lincoln County Process is what distinguishes "Tennessee Whiskey" from "Bourbon". However, not all producers of products labelled as Tennessee Whiskey use the process. (In particular, it is not used for production of Prichard's Tennessee Whiskey.)

To be labeled as a "Straight Bourbon", it is prohibited for flavoring or coloring compounds to be added to the spirit after the fermenting process. While it is a common misconception that this requirement prohibits the use of the Lincoln County Process for bourbons, it is actually not uncommon for bourbons to be charcoal filtered, and the decision not to label whiskies that use the process as "bourbon" may only be a choice of marketing strategy.

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 the term 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 whisky produced in the State of Tennessee". None of these regulations require the use of the Lincoln County filtering process (or any other filtering process).