Sunan an-Nasa'i, Volume 6, Book 51, Hadith 5708 (DarusSalam) ⓘ
It was narrated from Abu Rafi' that : 'Umar bin Al-Khattab, may Allah be pleased with him, said: "If you fear that Nabidh may be too strong, then weaken it with water." 'Abdullah (one of the narrators) said: "Before it gets strong."
أَخْبَرَنَا سُوَيْدٌ، قَالَ أَنْبَأَنَا عَبْدُ اللَّهِ، عَنِ السَّرِيِّ بْنِ يَحْيَى، قَالَ حَدَّثَنَا أَبُو حَفْصٍ، - إِمَامٌ لَنَا وَكَانَ مِنْ أَسْنَانِ الْحَسَنِ - عَنْ أَبِي رَافِعٍ أَنَّ عُمَرَ بْنَ الْخَطَّابِ رضى الله عنه قَالَ إِذَا خَشِيتُمْ مِنْ نَبِيذٍ شِدَّتَهُ فَاكْسِرُوهُ بِالْمَاءِ - قَالَ عَبْدُ اللَّهِ - مِنْ قَبْلِ أَنْ يَشْتَدَّ .
also referenced under: Hadith 5705 (Reference) & Book 51, Hadith 167 (In-Book)