I’m such a huge fan of using a double boiler in cooking and baking that I thought I’d write up a tutorial. Enjoy!
Basically all a double boiler is is a pot of boiling water under a heat safe bowl. The point is to use high, yet indirect, heat to cook or melt something. The advantage to the double boiler method is that the heat is even but not scorching or scalding. It’s also great because you get the benefits of high heat without any steam or added moisture.
There are plenty of fancy double boilers than you can buy but I prefer a simpler set up: a big (heat safe) glass bowl over a sauce pot full of boiler water.
The instructions are simple: fill the sauce pot with a few inches of water, bring to a boil, fit the big bowl on top, and then cook in the big bowl.
The big bowl on top should fit snugly: it shouldn’t sink all the way into the pot and it shouldn’t be resting on the rim either. It should sit tightly, about 2-3 inches into the pot.
The final critical piece of the bowl placement is water level. The boiling water should never actually touch the bowl. This is why I bring the water up to a full boil before fitting the bowl on top – it will allow you to see if the bottom of the bowl is going to touch the boiling water. If you’ve overfilled the sauce pot, just pour some of the water out into the sink and replace the bowl. As you can see below, you should be able to see the water boiling through the bottom of the bowl and the moisture collecting on the underside, but you should make sure it the two don’t actually touch.
My most common use for a double boiler is melting chocolate. I find that melting chocolate in the microwave is too prone to seizing up. So, for me, the constant, indirect heat of the double boiler provides the best conditions to melt chocolate. You can also make custard in a double boiler or melt other pesky foods like butter or peanut butter. It’s basically a great way to avoid burning anything delicate or sensitive that requires constant stirring.
Once you’ve added whatever you’re cooking to the big bowl, you’re going to need to stir it. Always wear an oven mitt! All that steam coming from the boiling water has to escape somehow. It creeps up the sides of the bowl and escapes all around it. This heats up the sides of the bowl as well as the bottom and gets extremely HOT. Be careful, cover your hands!
Another important note about stirring is what utensil you use. For smaller amounts like a little bit of butter, I like a small spatula. For bigger amounts like chocolate chips, I prefer a larger, sturdy spatula (here’s my favorite one). In any case, my preference is to use something made of silicone. It doesn’t conduct heat and is very easy to clean, especially when stirring sticky things like chocolate or peanut butter.
My last tip when using a double boiler is that whenever you’re finished cooking, remove from the heat as quickly as you can. But remember, the bottom of that bowl is going to be very hot. Before placing it directly on the counter or table, use a trivet. My favorite trivet is a cork one I got from IKEA ages ago.