A mix drink Scotch and soda used it as a base.
Scotch was a favorite beverage of Montgomery Scott, especially compared to other beverages such as vodka. Over the years Scotty developed a taste for the beverage, to the point that he was able to tell when the Scotch was replicated. (TOS episode: "The Trouble with Tribbles"; TNG episode: "Relics")
Scotty offered a "wee nip" of Scotch to General Korrd during a diplomatic reception on board the USS Enterprise. Korrd found Scotch more to his liking that the other beverages being offered at the party. Scotty remarked that he never thought he'd be drinking with a Klingon. (TOS movie: Star Trek V: The Final Frontier)