legal
Straight bourbon whisky
Defined in law
Bourbon stored in charred new oak barrels at 125° proof or less for a minimum of two years, with no neutral spirits and no colouring, flavouring or blending materials.
Where it is defined
27 CFR 5.143(c) Table 1 item (5); age-statement rules at 27 CFR 5.74(b)
Often confused with the 'four-year rule'
The minimum for 'straight' is two years, not four. Four years is the threshold above which an age statement becomes optional — any whisky under four years old must carry one.
Worth knowing
So a two-year-old straight bourbon is perfectly lawful but must say '2 years old'. 'Straight' also blocks additions absolutely: under 27 CFR 5.155(c)(3) any material added forces redesignation.
Related terms
Last reviewed 2026-07-30 · All glossary terms