in den sauren Apfel beißen (in dayn ZOW-ren AHP-fel BYE-sen) Literally “to bite into the sour apple” From sauer (sour) + apfel (apple) + beißen (to bite). The saying was already used by Martin Luther in the 1500s and comes from the idea that necessity sometimes leaves only the sour apples. It means doing something unpleasant because it must be done.