Sweating onions is done to accomplish for several purposes. Sweating gently cooks the onion to soften its texture, increase its sweetness and to reduce the sulfur content, which gives it a milder taste. Sweating onions for dishes, such as risottos, rice pilafs and braised meats is where the flavor begins. The sweat onions give a natural sweetness to dishes. See the instructions below for sweating onions.