Abu Sa'id reported that Messenger of Allah ﷺ prohibited us to mix grapes and dry dates together and unripe dates and dry dates (to prepare Nabidh.
نَهَانَا رَسُولُ اللَّهِ ﷺ أَنْ نَخْلِطَ بَيْنَ الزَّبِيبِ وَالتَّمْرِ وَأَنْ نَخْلِطَ الْبُسْرَ وَالتَّمْرَ