oversouring

Verb

oversour (third-person singular simple present oversours, present participle oversouring, simple past and past participle oversoured)

1. (intransitive) To become too sour.
   • On warm days the milk might oversour, while on cooler days it would be found comparatively sweet unless a good deal of attention was given to keeping the temperature where it would sour in the proper length of time.1914, John Michels, Creamery Butter-making, page 85

See all 2 meanings of oversour