Sometimes when working with things like chocolate, custards and fondant it's important to have slow, even, consistent heating. This ensures that your ingredients don't become too hot too fast or too much, which can cause them to break down. Other times you might want to work with something like melted chocolate for an extended period of time and not worry about constantly adjusting the heat to ensure that it's evenly melted. This is where a double boiler comes to the rescue. It's like cruise control for your heat!
A double boiler is a specific piece of cookware consisting of two fitted pots. The bottom pot is filled with 1 to 3 inches of water and the top pot fits above it and holds the ingredient that you're heating.
The whole setup is placed over a burner and heated until the water gets hot enough to heat your desired ingredient to your desired heat level. Usually you'll want to get the water boiling for best results, then turn off the heat when your ingredient gets to your preferred temperature.
The key thing to remember when using a double boiler is that the top pot should not come in contact with the water in the bottom pot. The double boiler does it's job best when the top pot is separated by the water in the bottom pot by a layer of air. This ensures that whatever you place in the top pot will be heated evenly, consistently and remain at that temperature for a considerable amount of time.
There's all sorts of double boilers available for you to buy but chances are you already have one if you have a stock pot or large saucepan and a metal, ceramic or glass mixing bowl. Just fill up the bottom pot with a few inches of water, bring it to a boil, then place your mixing bowl of choice on top so it's resting partially inside the bottom pot. If you really wanted to geek out on double boilers (and I know you do) you could use ceramic or glass for the top pot because it transfers heat even less than metal so it would heat your preferred ingredient even more evenly, producing as few hot spots as possible. Another benefit of using a double boiler is that you can remove the top pot, place plastic wrap on it and keep it in the fridge if you have leftovers you'd like to use at a later time. So next time you're working with chocolate, fondant or other heat sensitive ingredients, save yourself the stove drama and build yourself a double boiler.
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