Literally: Turning to vinegar
Meaning: To go sour; the situation is deteriorating; when a conversation takes a bad turn.
Origins: Started as a metaphor, as when the wine becomes sour and turn into vinegar, to depict the moment when things are turning nasty between two people arguing. It comes from Vinaigriers, street vendors selling vinegar, walking Paris’ streets and to attract customers would yell to announce their passage. In 1650, there were about 600 of them walking the streets and loudly announcing their passage with the phrase: “voila le bon vinaigre.”/here comes the good vinegar. Which as soon as 1660 created the expression: “crier au vinaigre.”/ yell vinegar.At the end of the 19th century, the metaphor turned into a familiar expression.
Synonyms: Tourner à la bagarre; Mal tourner
Examples:La conversation allait tourner au vinaigre/the conversation was about to turn nasty.