Musannaf Ibn Abi Shaybah

It is narrated from Hazrat Samak bin Musa Dhabbi, he says that I saw the slave girl of Hazrat Anas bin Malik (may Allah be pleased with him) breaking ripe dates from the stem side among the half-ripe dates. So this slave girl used to prepare nabidh separately from the ripe dates taken from the stem side, and used to prepare nabidh separately from the half-ripe dates.