How to Use a Double Boiler. A double boiler is a cooking device that consists of a saucepan partially filled with boiling water with another bowl or pot inside of it, the contents of which are heated through contact with the boiling water. Double boilers ensure slow, even heating and are handy for melting wax or chocolate, or cooking any sauce that is too delicate for direct heat. Double boilers can easily be improvised, if necessary.
Construct a double boiler if you don't own one by placing a metal or heat-safe glass bowl inside of a larger saucepan.
Fill the saucepan partially with water. Place the bowl portion of your double boiler inside the pan to make sure it will not displace too much water and cause a spill.
Remove the bowl, and heat the water to boiling.
Place a metal cookie cutter in the pot before adding the bowl to make sure that the bowl will never touch the bottom of the pot and heat too quickly or become too hot.
Add the bowl portion of the double boiler, and follow cooking instructions.
Pay constant attention to the double boiler. Many of the foods or sauces you will cook require constant stirring, even though there is less danger of overcooking or scorching in a double boiler.
Never allow the bowl of the double boiler to touch the bottom of the pan with the boiling water in it, as this creates direct transfer of heat and defeats the purpose of cooking with a double boiler. Boiling water does not rise above 212 degrees Fahrenheit. If you are cooking a candy recipe that requires ingredients to be hotter than 212 degrees, you will need to use a thick-bottomed pan heated slowly instead of a double boiler.
When melting wax in a double boiler, use an electric heat source rather than gas. Melting wax produces flammable fumes that may ignite if you have an open flame.