Because arborio rice undergoes less processing than long grain rice, it retains more of its natural starch content, which makes it perfect for risotto dishes. Cooking arborio rice releases this starch, resulting in a firmer, chewier rice and creamier sauce. Long grain rice will typically turn mushy and not give you the same results, but it can be used if this is all you have. Just keep an eye on the cooking times, as they may vary slightly.