Tennessee Whiskey · The Lincoln County Process
What is the difference between Lincoln County Process and bourbon?
Bourbon is a regulatory category; the Lincoln County Process is a single production step. They are different kinds of thing, which is why the comparison feels off. Bourbon is defined by federal rules about grain bill, distillation proof, and barrel type. The Lincoln County Process is a step done to a spirit before it enters the barrel: filtering it through sugar-maple charcoal. The comparison most searchers are actually reaching for is bourbon vs. Tennessee whiskey, where Tennessee whiskey shares every bourbon rule and adds the charcoal step. Where that leaves Prichard's, and what the charcoal actually changes, is where the question gets interesting.
What is the Lincoln County Process, and what makes bourbon bourbon?
Bourbon's definition lives in federal law. The Standards of Identity for Distilled Spirits set the rules: at least 51% corn in the grain bill, distilled to no more than 160 proof, entered into a new charred oak barrel at no more than 125 proof, and made in the United States. No coloring, flavoring, or additives. A whiskey that meets every one of those conditions is bourbon, regardless of state.
The Lincoln County Process happens at one specific point in production. After distillation, before the spirit goes into a barrel, it is run through a thick column of sugar-maple charcoal. The column is typically several feet deep, and the spirit trickles through it slowly, sometimes for several days. What comes out the bottom is the same whiskey, with some of its rougher flavor compounds left behind in the charcoal.
These are different kinds of thing. Bourbon is a regulatory bucket. The Lincoln County Process is a stage of production. A whiskey can sit inside the bourbon bucket and still pass through (or skip) the charcoal step.
| Bourbon (federal standard) | Lincoln County Process (the step) | ||
|---|---|---|---|
| Where made | United States | Where used | Tennessee (by state law); permissible elsewhere |
| Mash bill | At least 51% corn | What it is | Filtration through sugar-maple charcoal |
| Distillation proof | 160 proof maximum | When in production | After distillation, before barreling |
| Barrel-entry proof | 125 proof maximum | Material | Charcoal made from sugar-maple wood |
| Cask | New, charred oak | Duration | Several days (Jack Daniel's runs roughly 10 feet of charcoal; Angel's Envy notes up to 10 days) |
| Additives | None permitted | What it leaves behind | A portion of fusel oils and other heavy congeners |
| Charcoal step | Not required, not prohibited | Effect on flavor | Lighter, sweeter starting point for maturation |
Is Tennessee whiskey just bourbon that went through the Lincoln County Process?
Yes, with two caveats. Tennessee whiskey must meet the full federal bourbon standard, must be made in Tennessee, and must use the Lincoln County Process. Every bottle of Tennessee whiskey would qualify as bourbon by federal rules if not for the place-of-origin requirement and a Tennessee state statute (TN Code § 57-2-106, codified in 2013) that mandates the charcoal step.
The first caveat is marketing. Producers do not call Tennessee whiskey bourbon, even though it meets the bourbon definition. Jack Daniel's and George Dickel label their whiskey Tennessee whiskey by choice and by state law. The category exists as a separate identity, not as a subtype of bourbon on the bottle.
The second caveat is the Prichard's exemption. Benjamin Prichard's Distillery, in Kelso, Tennessee, holds a grandfathered exemption from the 2013 statute and does not use the Lincoln County Process. Its product is still legally labeled Tennessee whiskey. So the rule is "Tennessee whiskey must use the Lincoln County Process, except for Prichard's."
The labeling question is its own knot: even though Tennessee whiskey meets every federal definition of bourbon, no producer puts the word bourbon on a Tennessee whiskey label, and the categories are kept distinct in trade and in conversation.
Can a bourbon use the Lincoln County Process and still be called bourbon?
Federally, yes. Nothing in 27 CFR § 5.143 prohibits charcoal filtration before barreling. A whiskey distilled in Kentucky from a 70% corn mash bill, entered into new charred oak at 120 proof, and run through sugar-maple charcoal for three days on the way is still bourbon by every federal rule that matters.
The reason almost no one does this is two-part. The producers who built the modern process around Tennessee identity treat it as an identity step, not a portable technique, and most other distillers see no reason to copy a competitor's signature. And Tennessee state law restricts the term Tennessee whiskey to spirits made in the state. A Kentucky producer can run new-make through charcoal and label the result bourbon, but cannot trade on the more famous category name.
The Lincoln County Process is technically portable. In practice it is a Tennessee signature, used by Tennessee producers as part of how the category presents itself. Federally, a bourbon that runs through sugar-maple charcoal stays a bourbon, and the rule that prevents Kentucky producers from borrowing the term Tennessee whiskey is a state-law geographic restriction, not a federal one.
How does the charcoal step actually change the whiskey?
The flavor result, in plain language, is that the spirit going into the barrel is softer, sweeter, and less aggressive than it would have been without the step. New-make whiskey, fresh off the still, carries a load of harsher flavor compounds that mature into something balanced over years in oak. The Lincoln County Process strips a portion of those compounds out before the clock starts.
The mechanism is adsorption. Sugar-maple charcoal is highly porous, meaning the surface of every chip is riddled with tiny channels and pores that give it a vast amount of internal surface area for its volume. As the new-make spirit trickles through several feet of this charcoal over the course of days, certain flavor compounds in the whiskey bind to the surface of the charcoal. They stay there. The whiskey that comes out the bottom has lost some of them.
The compounds that get stripped most are the ones that matter most to the result. Fusel oils are the higher alcohols (heavier than ethanol) that fermentation produces alongside ethanol. They carry the hot, solvent-like, paint-thinner edge that all young spirits have to some degree, and the charcoal removes a meaningful fraction of them. Congeners is the umbrella term for the trace flavor compounds carried over from fermentation and distillation alongside the ethanol. Fusel oils are one type of congener, and several others (sulfur compounds, certain aldehydes) also bind to charcoal more readily than to the lighter, sweeter compounds the producer wants to keep. The corn-derived sweetness that defines a high-corn mash bill is largely intact at the end of the process.
That is what "smoother and mellower" actually means in this context. The descriptor is accurate, but it skips the reason: the charcoal has taken some of the spikier compounds out of the equation before the barrel has a chance to do its own work. The result is a whiskey that arrives in the cask already partway toward where maturation would take it, which is why the Lincoln County Process leaves Tennessee whiskey tasting softer and sweeter than a bourbon with the same mash bill. The spirit going in has already had its hardest edges trimmed. The Lincoln County Process is not bourbon's opposite, and not its replacement. It is a step that can be added to a whiskey already meeting the bourbon standard, and the question most searchers are reaching for is bourbon vs. Tennessee whiskey: one shared rulebook plus one extra production stage.