What word or phrase does your mother always say?
1814, from craunch (1630s), probably of imitative origin. Related: Crunched; crunching. The noun is 1836, from the verb; the sense of "critical moment" was popularized 1939 by Winston Churchill, who had used it in his 1938 biography of Marlborough.
: : It's Crunch Time in the Havensnoun