وَعَنْ أَنَسٍ أَنَّ النَّبِيَّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ سُئِلَ عَنِ الْخَمْرِ يُتَّخَذُ خَلًّا؟ فَقَالَ: «لَا» . رَوَاهُ مُسلم

Anas told that the Prophet was asked about wine which was turned into vinegar* and forbade it. Muslim transmitted it. * This is said to have been done by putting onions or salt in it, or by placing it in the sun.