According to Islamic teachings, the permissibility of wine vinegar depends on how it is produced:

Natural Conversion: If wine turns into vinegar by itself, without deliberate intervention, consuming it is considered halal vinegar. Natural vinegar is Halal based on a hadith where the Prophet Muhammad (PBUH) praised vinegar as a good food.

Deliberate Conversion: If wine is intentionally turned into vinegar through human intervention just like adding substances like vinegar, onions, salt, etc, then scholars have differing opinions on its halal or haram. The majority, including the Shafi’i, Hanbali, and some Maliki scholars, consider it haram based on hadiths that discourage handling or benefiting from wine, even when converting it to vinegar.

Therefore, whether wine vinegar is halal largely depends on whether its transformation from wine to vinegar was natural or deliberate. If it occurred naturally without human intervention, it is halal. If the transformation was deliberate, many scholars consider it haram.