- When filling the lower pan with water, it's important not to overfill because the water might boil over and escape from the pan, which could result in serious burns. Equally important is to avoid allowing the water in the lower pan to boil dry. If the water cooks away, more water will have to be added. The double boiler may have a water line, indicating how high to fill the pan. Before lifting the upper pan from the double boiler and exposing the lower pan of water, remove the double boiler from the heat source. Because steam may escape rapidly when the upper pan is removed, use caution to avoid burns.
- If a recipe calls for a double boiler and the kitchen doesn't have one, the cook can improvise by fitting together two pans, with the larger pan on the bottom and the smaller pan on top. Using a makeshift double boiler can be hazardous. A standard double boiler is designed so that the upper pan fits snugly over the water, containing the steam and preventing the contents in the upper pan from spilling over into the boiling water.
- When using a makeshift double boiler, avoid coming in contact with the steam to prevent burning the skin. Do not overfill either pan. Some substances that spill into hot water can result in dangerous flare-ups, and if the upper pan is overfull, it will increase this possibility. If the pans are close in size, they may lock together, making it nearly impossible to separate them. Never let the upper pan's bottom touch the lower pan's heated bottom. That will result in the upper pan's contents coming into direct contact with the heat source, thus defeating the purpose of a double boiler.
