Innis & Gunn was founded in 2003 by brewer Dougal Sharp, son of Russell Sharp, founder of Caledonian Brewing and Edinburgh Brewing. Innis and Gunn specializes in beers matured in American white oak casks from the state of Kentucky that were previously used for maturing bourbon. The newest product has now expanded the maturation to casks formerly used for rum aging as well. Brewing the beer takes roughly seven days. The beer is then racked to the oak casks where it matures for from one to thirty days (this is because every cask is different in its affect on the maturation process). After this time, the casks are emptied and the beer blended to be further aged in the "marrying tun" for thirty to seventy-seven days. The beer is then bottled. All casks are only used once.