أَخْبَرَنَا سُوَيْدٌ، قَالَ أَنْبَأَنَا عَبْدُ اللَّهِ، عَنْ بَشِيرِ بْنِ الْمُهَاجِرِ، قَالَ سَأَلْتُ الْحَسَنَ عَمَّا يُطْبَخُ مِنَ الْعَصِيرِ قَالَ مَا تَطْبُخُهُ حَتَّى يَذْهَبَ الثُّلُثَانِ وَيَبْقَى الثُّلُثُ ‏.‏

It was narrated that Bushair bin Al-Muhajir said: "I asked Al-Hasan about juice that has been cooked. He said: 'That which has been cooked until two-third of it has gone and one-third is left.'" Translation Not Available

Book Ref: Sunan An Nisai Book 51 Hadith 5725
Web Ref:  Sunan An Nisai Vol 6 Book 51 Hadith 5728