Sayyidah Umm Ma'bad bin Ka'b (may Allah be pleased with her) said: I heard the Messenger of Allah (peace and blessings be upon him) forbid mixing two things (when making nabidh), that is, mixing dry dates with unripe and fresh dates, and he (peace and blessings be upon him) said: "Drink each of them (prepared) separately."
Hadith Referenceالمعجم الكبير للطبراني / مسند النساء / 21815
Sayyidah Umm Ma'bad bin Ka'b (may Allah be pleased with her), who had prayed towards both qiblahs, narrates that the Messenger of Allah (peace and blessings be upon him) said: "Do not make nabidh by mixing dates and raisins; rather, make nabidh from each of them separately."
Hadith Referenceالمعجم الكبير للطبراني / مسند النساء / 21816