cask
Char level
No legal definition
The degree to which a barrel's interior has been burned to carbon before filling, graded by cooperages roughly #1 to #4 by exposure time — about 15 to 55 seconds. #4, the deepest, is 'alligator char'.
Not a legal term
No whisky regulation in Scotland, Ireland, the United States, the EU or Japan defines this. It is a trade or marketing term, so it is only actionable if its use is actively misleading.
Worth knowing
US law requires 'charred new oak' for bourbon but specifies no char grade, depth or duration; the #1–#4 scale is cooperage convention, not regulation. Char creates both a carbon filtration layer and the caramelised 'red layer' beneath it, which are chemically different contributions.
Related terms
Last reviewed 2026-07-30 · All glossary terms