cask
Barrel
Defined in law
Strictly, the American Standard Barrel of approximately 200 litres (53 US gallons) used for bourbon and then widely reused for Scotch and Irish maturation.
Where it is defined
27 CFR 5.1 and 5.143 require 'oak barrels' without prescribing a size, except the 700-litre maximum for American single malt whisky
Often confused with cask
'Cask' is the generic term for any size; 'barrel' properly denotes the ~200-litre ASB. In US labelling contexts 'barrel' carries regulatory weight — 'barrel proof', 'single barrel'.
Related terms
Last reviewed 2026-07-30 · All glossary terms