Sunan al-Nasa'i
The Book of Drinks — Hadith #5729
أَخْبَرَنَا مُحَمَّدُ بْنُ الْمُثَنَّى، قَالَ حَدَّثَنَا ابْنُ أَبِي عَدِيٍّ، عَنْ دَاوُدَ، قَالَ سَأَلْتُ سَعِيدًا مَا الشَّرَابُ الَّذِي أَحَلَّهُ عُمَرُ رضى الله عنه قَالَ الَّذِي يُطْبَخُ حَتَّى يَذْهَبَ ثُلُثَاهُ وَيَبْقَى ثُلُثُهُ .
“I asked Sa’eed: ‘What is the drink that ‘Umar bin Al-Khattab, may Allah be pleased with him, regarded as permissible?’ He said: ‘That which has been cooked until two-third has gone and one-third is left.'”
Chain of Narration (Isnad)