Learn about Puffed rice is traditionally made by subjecting paddy to HTST treatment, usually with heated sand. The effect of various processing conditions on puffing was studied using a small laboratory coffee roaster [using hot sand] and a small hot-air puffing system, using 25 g paddy in each experiment. The sand grade, sand:paddy ratio and roaster speed did not affect puffing significantly. The optimum conditions were: grain moisture of 14% (wet basis) in either system, and temp. for sand puffing at about 200 degree C, and for air puffing at 225 degree C at an air-flow rate of 1.5 m-3/min. Immature kernels did not puff well but cracked grains showed slightly increased puffed vol. Parboiling reduced puffing. Addition of salt increased puffed vol. appreciably and also shifted the optimum moisture content to 17%. Sun-drying of paddy before moisture adjustment substantially increased the puffed vol.