Charring casks reached an apogee in July 1935 when US Congress mandated the first standards of identity for producing straight classes of domestic American whisky: “must be kept in new oak containers, charred if used for whisky.” Today, the regulations state that for bourbon, rye, wheat, and malted straight whisky, the vessel in which the spirit must be aged is a charred new oak barrel. No other country or alcoholic beverage mandates the charring or use of new casks as a requirement for a national class of whisky.
The charring of barrels was introduced to America by Europeans in the 18th century when distillers of rye and corn mashes used the charcoal membrane inside the barrels to filter and treat raw spirits. By the 1870s, charred barrels remained in minority usage as the Internal Revenue Record reported high wines from “Bourbon steam (whisky) is, and generally is drawn off into unburnt barrels”.
