Al-Kāfi - Volume 6 > Al-Tila’ (The One-Third Juice (grape juice) that has Remained after the Evaporation of the other Two-Thirds)
Hadith #10

عِدَّةٌ مِنْ أَصْحَابِنَا عَنْ سَهْلِ بْنِ زِيَادٍ عَنْ مُوسَى بْنِ الْقَاسِمِ عَنْ عَلِيِّ بْنِ جَعْفَرٍ عَنْ أَخِيهِ أَبِي الْحَسَنِ مُوسَى ( عليه السلام ) قَالَ سَأَلْتُهُ عَنِ الزَّبِيبِ هَلْ يَصْلُحُ أَنْ يُطْبَخَ حَتَّى يَخْرُجَ طَعْمُهُ ثُمَّ يُؤْخَذَ ذَلِكَ الْمَاءُ فَيُطْبَخَ حَتَّى يَذْهَبَ ثُلُثَاهُ وَ يَبْقَى الثُّلُثُ ثُمَّ يُرْفَعَ وَ يُشْرَبَ مِنْهُ السَّنَةَ فَقَالَ لَا بَأْسَ بِهِ .

10. A number of our people have narrated from Sahl ibn Ziyad from Musa ibn al-Qasim from Ali ibn Ja‘far from his brother abu al- Hassan, ‘Alayhi al-Salam, who has said the following: “I once asked abu al-Hassan, ‘Alayhi al-Salam, about raisins; if it can be boiled to extract its sweetness, then that water is boiled until its two-thirds are evaporated and only one-third is left; then it is taken away to use for drink during the year. He (the Imam) said, ‘It is not unlawful.’”