What is the origin of the idiom "sour as vinegar" and when to use it?

The idiom "sour as vinegar" is an idiomatic expression that has been in use for centuries. The comparison between sourness and vinegar likely originates from the distinct taste and pungent aroma of vinegar. Vinegar is made through a fermentation process and has a sharp, acidic flavor that can evoke a strong reaction. The phrase can be used in various situations, such as describing someone's response to criticism, their general outlook on life, or their interactions with others. It is often used to emphasize the extent of someone's negative attitude or behavior, likening it to the sharp, acidic taste of vinegar.