´It was narrated that Sa'eed bin Al-Musayyab said:` "When At-Tila' (thickened grape juice) has been cooked and reduced to one-third, then there is nothing wrong with it."
Hadith Referenceسنن نسائي / كتاب الأشربة / 5726
Hadith Gradingالألبانی:صحيح الإسناد مقطوع | زبیر علی زئی:إسناده صحيح