IR 64 IR-64 parboiled rice is a variation of IR-64 rice that has undergone the parboiling process. Parboiling is a method of processing rice in which the raw grains are pre-soaked, steamed under pressure and then dried. This process changes the starch structure in the grains, making them more nutritious and providing a firm texture after cooking. IR-64 Parboiled rice often retains some of the bran, giving it a darker color. It is also known for its resistance to warping during cooking, making it a popular choice in many kitchens.