Small scale milling of wheat flour in a roadside shop
This is a video of a flour mill with two stones in a small shop outside the gates of Punjab Agricultural University, Ludhiana, India. The film shows the grain being poured into the hoppers above the stones, and then going between the millstones. From one stone set, the brown/wholemeal flour goes into sacks; in the other, it goes straight onto a shaking sieve, with the bran and germ going to the back and the white flour coming out of the front of the sieve. It is then collected and bagged, here in 10kg sacks, for use without further grinding or bleaching. The mill also makes maize meal and gram (lentil/chickpea) flour. The wheat flour will be mostly used for making chapati (chappati) or roti breads, thin dough cooked on a heated stone. The flour has high gluten content to give the elasticity to the dough so it can be stretched to be thin.
The YouTube video of the mill grinding wheat flour and its sieves is at http://youtu.be/1tPWqpj4680
In the west, most flour is milled using multi-stage roller mills that first remove the bran and germ, and then grind the flour/starch/endosperm, usually slightly finer that this mill. In this shop, the separation of the two stones can be adjusted to change fineness while they are running, a process not shown in the video. In the Punjab and Ludhiana, there were several similar roadside shops for flour mills (some with only one stone pair), and other shops which crushed oilseeds for oil and meal.