"crudeness, earthiness," 1963 (in Billboard magazine, describing lead guitar on surf music tracks), back-formation from raunchy. There was a singing group in U.S. c. 1960 called the Raunch Hands.
Entries linking to raunch
raunchy adj.
1939, "clumsy, careless, sloppy; a name applied to anything that is dirty or in bad shape," U.S. Army Air Corps slang, a word of unknown etymology. Origins among cadets in Texas suggest a possible connection to Mexican Spanish rancho (see ranch (n.)), which had connotations of animal filth by 1864; raunch was an old alternative English spelling of ranch. Sense of "coarse, vulgar, smutty" is from 1967. Related: Raunchiness.