Al-Kāfi - Volume 6 > The Juice (grape juice)
Hadith #3

مُحَمَّدُ بْنُ يَحْيَى عَنْ أَحْمَدَ بْنِ مُحَمَّدٍ عَنْ أَبِي يَحْيَى الْوَاسِطِيِّ عَنْ حَمَّادِ بْنِ عُثْمَانَ عَنْ أَبِي عَبْدِ اللَّهِ ( عليه السلام ) قَالَ سَأَلْتُهُ عَنْ شُرْبِ الْعَصِيرِ فَقَالَ اشْرَبْهُ مَا لَمْ يَغْلِ فَإِذَا غَلَى فَلَا تَشْرَبْهُ قَالَ قُلْتُ جُعِلْتُ فِدَاكَ أَيُّ شَيْ‏ءٍ الْغَلَيَانُ قَالَ الْقَلْبُ .

3. Muhammad ibn Yahya has narrated from Ahmad ibn Muhammad from abu Yahya al-Wasitiy from Hammad ibn ‘Uthaman who has said the following: “I once asked abu ‘Abd Allah, ‘Alayhi al-Salam, about drinking juice (grape juice). He (the Imam) said, ‘You can drink it before it is boiled. Once it is boiled then do not drink.’ I then asked saying, ‘I pray to Allah to keep my soul in service for your cause, what is boiling?’ He (the Imam) said, ‘It is fluctuation (fermentation) and change.’”