Bran separators use an air stream to separate the lighter bran, which is carried upwards by the air flow, while the heavier bulgur grains remain below. This process uses air flow to separate the light materials from the bulgur grains, based on the density of the particles. Vibrating surfaces are used to facilitate the separation of bulgur grains and bran. The weight difference between bulgur grains and bran forms the basis of the separation process.