Bourbon, Rye and Tennessee: The Rules and the Styles

Scotch has its regions; American whiskey has its rulebook. The federal Standards of Identity, written into the Code of Federal Regulations, decide what may be called bourbon or rye, and in 1964 Congress recognised bourbon as a distinctive product of the United States. Learn the rules and every label becomes a technical sheet. You will know what the grain, the barrel and the proof are telling you before you open the bottle, and why a Kentucky bourbon and a Tennessee whiskey taste like cousins rather than twins.

Bourbon: the rules on the label

• Made in the United States from a mash of at least 51% corn.
• Distilled to no more than 80% ABV (160 proof).
• Entered into the barrel at no more than 62.5% ABV (125 proof).
• Stored in new, charred oak containers; every bourbon barrel is used once for bourbon, which is why Scotland has so many of them.
• Bottled at no less than 40% ABV, with no colouring or flavouring added.
• No minimum age, but straight bourbon must spend at least two years in new charred oak, and a straight whiskey under four years must state its age.

In bourbon, the barrel is never second-hand. That single rule explains its sweetness.

Rye and Tennessee

Rye whiskey follows the same distillation, barrel-entry and new charred oak rules, with at least 51% rye in the mash; expect pepper, clove and a drier finish. Tennessee whiskey is defined by a 2013 state law: it must be made in Tennessee, meet the bourbon-style grain and proof limits and be filtered through or steeped in maple charcoal before ageing. That step, the Lincoln County Process, softens the new spirit. Benjamin Prichard's holds an exemption from it. In practice, the charcoal step is what sets most Tennessee whiskeys apart from bourbon.

• Bottled in Bond: from one distiller, one distillery and one distilling season, aged at least four years in a bonded warehouse and bottled at 100 proof, under a law dating from 1897.
• Single barrel: one barrel bottled on its own, so each release can vary.
• Barrel proof or cask strength: bottled without dilution, so add water with care.

Styles worth knowing

• Traditional bourbon: corn sweetness with rye as the secondary grain, balanced and versatile.
• High-rye bourbon: more rye in the mash for spice and lift.
• Wheated bourbon: wheat replaces rye as the secondary grain for a softer, rounder profile.
• Rye: from barely legal 51% mashes to near all-rye recipes. Try one neat and one in an Old Fashioned, and drink in moderation.