Quality millet grain size, color uniform, milky white, yellow or golden yellow, shiny, very few broken rice, no insects, no impurities. Take a few test placed on the soft white millet grain fragrant grains how much a pound wholesale, and breathe incense grains and cereals to wet the wholesale price, then rub with a paper spill millet several times to observe whether there is a slight yellow paper if yellow grain fragrant grains, indicating that the test millet stained yellow pigment. In addition, a small sample can be wetted with water, the water color changes observed, if slightly yellow, indicating mixed with yellow pigment. Millet stained chemical identification method: take samples of 25 g placed in a mortar, add 25 ml of ethanol, grind grain fragrant grains which brand is good, whichever suspension 25 ml, placed in colorimetric tube, then added 2 ml of 10% sodium hydroxide, shaking uniform, standing a moment to observe the color change, if it is orange, indicating that millet is stained with curcumin.