Ibn Abbas reported that Messenger of Allah ﷺ forbade, the preparation of Nabidh in gourd, in varnished jar, hollow stump and from mixing up ripe dates with nearly ripe dates. (Using translation from Muslim 17f)  

«نَهَى النَّبِيُّ ﷺ عَنِ الدُّبَّاءِ وَالْحَنْتَمِ وَالْمُزَفَّتِ وَالنَّقِيرِ وَأَنْ يُخْلَطَ الْبَلَحُ بِالزَّهْوِ»