- fermentation occurring in canned foods after sealing.
- canned food so fermented.
Origin of flat sour
First recorded in 1925–30
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
Examples from the Web for flat sour
This "flat-sour" is not harmful and must not be confused with "botulinus," which is harmful.
However, the taste and odor are so disagreeable you will have no desire to eat "flat-sour" canned goods.
Flat-sour often causes annoyance to beginners in canning some vegetables, such as corn, peas, beans and asparagus.