"At the time of the Messenger of Allah, the people used to give as Sadaqatul Fitr a Sa' of barely or dates or rye or raising." (Using translation from Nasāʾī 2516)  

عَنْ صَدَقَةِ الْفِطْرِ فِي عَهْدِ رَسُولِ اللهِ ﷺ «صَاعًا مِنْ شَعِيرٍ أَوْ تَمْرٍ أَوْ سُلْتٍ أَوْ زَبِيبٍ»