Kellerun citrus mash was an alcoholic beverage produced by the Kellerun.
In 3191, Commander Rayner promised a cask of Kellerun citrus mash to the USS Discovery crew member who could solve the problem of extracting the ISS Enterprise through an intermittent wormhole from a pocket of interdimensional space. Since the solution came from group effort, he offered mash all around. (DIS: "Mirrors")