1- Vinegar is a well-known basic foodstuff, made from wine of which the composition has changed so that it is no longer sweet but is acidic or sour. 2- When wine turns to vinegar by itself, without any deliberate treatment needed for it to be changed, it is permissible to eat, drink and handle. 3- If the wine has become vinegar because of deliberate treatment, by adding vinegar, onions, salt etc., or by any other process, in this case the scholars differ as to whether it is permissible or not. For more, see the detailed answer.