Brown rice and white rice come from the same plant; the difference is in the milling process. While brown rice contains all three parts of the grain (bran, layer and endosperm), white rice is milled until the bran and germ are removed.
Once harvested, rice grains are sent to the mill where excess moisture is removed using a massive dryer and then cleaned, to separate whole grains from straw and broken grains. Next, the rough rice hulls are shelled to reveal the rice grain and expel the hulls, yielding wholegrain brown rice. If white rice is desired, brown rice is milled by removing the bran, yielding polished white rice.