Double boilers are excellent tools for reheating or slowly melting certain ingredients without burning them. However, it's important to set them up correctly. You need to use a saucepan and a mixing bowl that's slightly larger in size. Fill the saucepan with water, and place the mixing bowl on top. The water should not touch the bowl once in place. Also remember to turn the heat down after the water comes to a boil to avoid cooking the preparation.