The Lincoln County Process: What Actually Makes Tennessee Whiskey Different

Ask most people what makes Tennessee whiskey different from bourbon, and you'll get a shrug or a guess about geography. The real answer is more specific, and it's written into state law: the Lincoln County Process.

What the Lincoln County Process Actually Is

Before new-make whiskey ever touches a barrel, it's filtered through (or steeped in) a thick bed of sugar maple charcoal. This step, known as charcoal mellowing, strips out some of the fusel alcohols responsible for a harsher, more aggressive spirit. The result is a smoother new-make that then goes into new charred oak barrels for aging, same as bourbon. The charcoal itself is typically made on-site, burned down from stacked sugar maple timbers, then packed into vats that can run 10 to 13 feet deep depending on the distillery.

It's Not Just Tradition — It's Law

For most of Tennessee whiskey's history, the Lincoln County Process was just how things were done, not something written into any statute. That changed in 2013, when Tennessee signed House Bill 1084 into law, codified as Tenn. Code Ann. § 57-2-106. The law requires that anything labeled "Tennessee Whiskey," "Tennessee Whisky," or "Tennessee Sour Mash Whiskey" meet a specific set of standards, largely mirroring the federal requirements for bourbon (a mash bill of at least 51% corn, aging in new charred oak, distillation and barrel-entry proof limits) plus one addition unique to Tennessee: the whiskey must be filtered through maple charcoal before it goes into the barrel.

The One Distillery That Doesn't Use It

There's exactly one legal exception: Benjamin Prichard's Distillery, based in Kelso, Tennessee. The exemption exists because founder Phil Prichard argued, successfully, that his ancestor Benjamin Prichard's original 19th-century whiskey recipe predates the charcoal-filtering technique entirely, meaning it was never part of the historical process he was reviving. Lawmakers wrote the carve-out directly into the statute, and Prichard's remains the only Tennessee distillery permitted to sell whiskey labeled "Tennessee Whiskey" without ever running it through the Lincoln County Process.

Here's the detail that makes this genuinely ironic: Prichard's is located in Lincoln County itself, the very county the process is named after. It's the last operating distillery there, and it's the one distillery in that county that skips the process bearing its name.

What Happens If You Skip It

Outside of Prichard's grandfathered exemption, no other Tennessee distillery gets to skip the process and still use the "Tennessee Whiskey" name. Some craft producers in the state choose to bypass charcoal mellowing on purpose, whether to chase a different flavor profile or avoid the added production time and cost. That's a legitimate choice, but the tradeoff is the label: a Tennessee-made whiskey that skips the Lincoln County Process has to be sold as bourbon (if it meets bourbon's federal requirements) or American whiskey instead. It's not a loophole or a workaround. The law simply ties the name to the process, not just the zip code.

Two Takes on the Same Process

Even among the distilleries that do use the Lincoln County Process, the execution varies. Jack Daniel's grinds its own charcoal into bean-sized pellets, packs them into vats around 10 feet deep, and lets new-make trickle through by gravity in a process the distillery says takes over a week. George Dickel does things a little differently: the whiskey is chilled before it ever reaches the charcoal, and the vats run deeper, around 13 feet, with the liquid filling the vat rather than trickling through it. Same law, same basic idea, different house style, which is a good reminder that "Tennessee Whiskey" is a category with more range inside it than the label might suggest.

Next time someone tells you Tennessee whiskey is "just bourbon made in Tennessee," you'll know the more precise answer: it's bourbon made in Tennessee, filtered through maple charcoal before barreling, with exactly one legally sanctioned exception to prove the rule.