From Sahih Bukhari (Hadith 5410):
Narrated Abu Hazim:that he asked Sahl, "Did you use white flour during the lifetime of the Prophet (ﷺ) ?" Sahl replied, "No. Hazim asked, "Did you use to sift barley flour?" He said, "No, but we used to blow off the husk (of the barley)
Reference: Bukhari 5410