Nafi' (may Allah have mercy on him) said: "By Allah!" Sayyiduna Umar (may Allah be pleased with him) only frowned at the water-flask when he tasted it because it had turned to vinegar. A similar narration also comes from Ibn al-Musayyib (may Allah have mercy on him). It is also reported from Utbah bin Farqad that the nabidh which Sayyiduna Umar (may Allah be pleased with him) drank had turned to vinegar. And Zayd bin Aslam (may Allah have mercy on him) said that the Companions (may Allah be pleased with them) used to break the strength of nabidh with water when it turned sour on them.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الأشربة والحد فيها / 17450