[Tennessee] Charcoal Mellowing - Lincoln County Process

Short write-up on charcoal mellowing. Corrections welcome.

What charcoal mellowing is

Before the distillate goes into an oak barrel, it’s filtered through sugar maple charcoal. Official name: the Lincoln County Process. This is the step that separates Tennessee whiskey from bourbon.

The principle is simple. Charcoal absorbs the harsher congeners in the spirit - fusel oils, sulphur compounds - and strips them out. The result is a smoother, rounder mouthfeel. The silky finish on Jack Daniel’s Old No. 7 and Single Barrel 100 Proof is what charcoal mellowing leaves you with.

Every distillery does it a little differently

• Jack Daniel’s - drips the spirit drop by drop through a charcoal bed around 3 metres deep, gravity only
• George Dickel - uses a roughly 4-metre bed, chills the spirit to about 4°C first, then steeps it in the charcoal (the “cold-chill” step)
• Collier and McKeel - pumps the spirit through the charcoal instead of relying on gravity

Tennessee whiskeys that use it

By Tennessee state law from 2013, anything labeled “Tennessee Whiskey” has to go through charcoal mellowing. The only exception is Benjamin Prichard’s, which was grandfathered in because they were already producing without the step when the law passed.

A rough list of the main Tennessee whiskeys:

1. Jack Daniel’s Old No. 7 - 40%, the icon
2. Jack Daniel’s Single Barrel Select - 47%, single barrel entry
3. Jack Daniel’s Single Barrel 100 Proof - 50%
4. Jack Daniel’s Gentleman Jack - 40%, charcoal-mellowed twice
5. George Dickel No. 8 - 40%, cold-chilled then steeped
6. George Dickel Barrel Select - 43%, the premium tier
7. Uncle Nearest 1856 - 50%, named after Nathan Green, the man who taught Jack Daniel charcoal mellowing
8. Nelson’s Green Brier - 45.5%, Nashville-based
9. Chattanooga Whiskey 111 - 55.5%, 2023 Craft Producer of the Year

Charcoal mellowing vs bourbon

Tennessee whiskey meets every legal requirement of bourbon - 51% corn minimum, new charred oak barrels, and the rest. The charcoal step is the only addition. Technically it meets bourbon specs; state law keeps it separate.

Pour Buffalo Trace or Knob Creek 9 Years next to a glass of Jack Daniel’s and you’ll pick out the charcoal-mellowing texture immediately.