Why Is Crème Caramel Baked in a Water Bath?

Crème caramel is essentially a mixture in which egg binds milk and sugar, and it sets entirely through the coagulation of the egg. There is a narrow range for coagulation: if it is slightly undercooked, the mixture runs; if it is slightly overcooked, the proteins contract too much. The oven’s dry heat warms the edges of the mold very quickly. A water bath slows this process and keeps the area around the mold near the boiling point of water. The same method is used for all baked desserts made with milk and eggs, including cheesecake, for the same reason.

You can see what happens when crème caramel is baked without a water bath when it is cut. The edges are firm, small holes have formed inside, and water pools around it when it is turned out onto a plate. These holes form when overheated proteins bind together and push out the water between them. The texture is rubbery and springs back when pressed with a spoon. When the same recipe is baked in a water bath, the cut surface is smooth and matte. Foam on the surface also contributes to holes; straining the mixture and removing the foam produces a cleaner cross-section.

Setup is simple, but there are a few details to keep in mind. Place the molds in a deep baking pan and fill the pan with hot water to halfway up the molds. Do not use cold water and wait for it to heat in the oven; hot water shortens the baking time and establishes the temperature balance from the start. Filling the pan after it has been placed in the oven reduces the risk of spills. If you place a cloth or paper under the molds, the metal does not touch metal and the heat distributes more evenly. Move slowly and use both hands when removing the pan from the oven because hot water may spill. Leave a few finger-widths of space between the pan and the molds so water can circulate around them.

The water should not boil. A bubbling water bath can splash water into the molds and cause the temperature to fluctuate, so keep the oven heat moderate. Covering the top of the pan with foil prevents a skin from forming on the surface and keeps its color from changing. Check doneness with the jiggle test: gently shake a mold. If the edges stay set while the center jiggles slightly, the dessert is ready. If you have a thermometer, the center should read at least 71°C / 160°F. Avoid opening the oven door unnecessarily; each time it is opened, the water-bath temperature drops and the baking time increases.

Cooling is also part of the process. Remove the molds from the hot water, let them cool to lukewarm at room temperature, and refrigerate them within 2 hours of baking for a few hours, preferably overnight. During this rest, the texture sets and the caramel at the bottom melts into a sauce. Crème caramel inverted too early falls apart. Run a thin knife around the edge of the mold, then invert it onto a plate to release it intact. Cover the molds with plastic wrap while they chill in the refrigerator; otherwise, the surface dries out and the caramel sauce does not melt enough.