I asked Sahl bin Sa`d, "Did Allah's Messenger (ﷺ) ever eat white flour?" Sahl said, "Allah's Messenger (ﷺ) never saw white flour since Allah sent him as an Apostle till He took him unto Him." I asked, "Did the people have (use) sieves during the lifetime of Allah's Messenger (ﷺ)?" Sahl said, "Allah's Messenger (ﷺ) never saw (used) a sieve since Allah sent him as an Apostle until He took him unto Him," I said, "How could you eat barley unsifted?" he said, "We used to grind it and then blow off its husk, and after the husk flew away, we used to prepare the dough (bake) and eat it."
Sahih al-Bukhari Book 70, Hadith 41
← Previous Hadith I was one of (the first) seven (who had embraced Islam) with Allah's Messenger (ﷺ) and we had nothing to eat then, except the leaves of the Habala or Hubula tree, so that our stool used to be similar to that of sheep. Now the tribe of Bani Asad wants to teach me Islam; I would be a loser and all my efforts would be in vain (if I learn Islam anew from them).

Sahih al-Bukhari Book 70, Hadith 40 Next Hadith → that he passed by a group of people in front of whom there was a roasted sheep. They invited him but he refused to eat and said, "Allah's Messenger (ﷺ) left this world without satisfying his hunger even with barley bread."

Sahih al-Bukhari Book 70, Hadith 42