Hadithcore
Sahih Muslim, 1981
sahih

Anas b. Malik is reported to have said that Allah's Messenger (ﷺ) had forbidden to mixture fresh dates and unripe dates and then drinking (the wine prepared out of it), and that was their common intoxicant when liquor was prohibited.

وَحَدَّثَنِي أَبُو الطَّاهِرِ، أَحْمَدُ بْنُ عَمْرِو بْنِ سَرْحٍ أَخْبَرَنَا عَبْدُ اللَّهِ بْنُ وَهْبٍ، أَخْبَرَنِي عَمْرُو بْنُ الْحَارِثِ، أَنَّ قَتَادَةَ بْنَ دِعَامَةَ، حَدَّثَهُ أَنَّهُ، سَمِعَ أَنَسَ بْنَ مَالِكٍ، يَقُولُ إِنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم نَهَى أَنْ يُخْلَطَ التَّمْرُ وَالزَّهْوُ ثُمَّ يُشْرَبَ وَإِنَّ ذَلِكَ كَانَ عَامَّةَ خُمُورِهِمْ يَوْمَ حُرِّمَتِ الْخَمْرُ ‏.‏

References2 variants
In-Book Reference
Book 36, Hadith 11
USC-MSA web (English) reference
Book 23, Hadith 4888 (deprecated numbering scheme)