This outer bran and germ discarded from the oats groats is termed as oat bran. Moreover, the oat groat (minus the oat bran) is passed through a steam roller which flattens the oats to a thickness of 0.3 to 1mm, oat bran is just the hull of oat groats. Oat bran is creamy in texture and mushy, thus, goes down really effortlessly.