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).  

أَنَّهُ سَأَلَ سَهْلاً هَلْ رَأَيْتُمْ فِي زَمَانِ النَّبِيِّ ﷺ النَّقِيَّ قَالَ لاَ فَقُلْتُ فَهَلْ كُنْتُمْ تَنْخُلُونَ الشَّعِيرَ قَالَ لاَ وَلَكِنْ كُنَّا نَنْفُخُهُ