The United States Congress designated bourbon as a distinctive product of the United States in 1964.
The designation recognized bourbon’s distinctive American production tradition and protected the name from being used for unrelated spirits. Bourbon is made from a grain mixture containing at least 51% corn, distilled to no more than 160 proof, and entered into new, charred oak barrels at no more than 125 proof.
Bourbon can be made anywhere in the United States; Kentucky is strongly associated with it because of its long distilling history, limestone water, and climate. Contrary to a common misconception, bourbon does not have to be made in Kentucky.
The 1964 congressional action helped establish bourbon as a protected American identity comparable to the geographical traditions associated with Scotch whisky or Cognac. Straight bourbon must mature for at least two years, although bourbon itself has no general minimum aging period.