Zakat (Kitab Al-Zakat)
Dawud :: Book 9 : Hadith 1614
Narrated AbuSa'id al-Khudri:
I shall always pay one sa'. We used to pay during the lifetime of the Apostle of Allah (peace_be_upon_him) one sa' of dried dates or of barley, or of cheese, or of raisins. This is the version of Yahya. Sufyan added in his version: "or one sa' of flour." The narrator Hamid (ibn Yahya) said: The people objected to this (addition); Sufyan then left it.