Recipes engineered for perfection—what exactly does that mean? The Science series takes you inside the experiments behind 50 cooking concepts featured in our new book, The Science of Good Cooking, by the editors of Cook’s Illustrated.
Cheesecakes are notoriously tricky things. Even when you measure your ingredients carefully, even if your oven temperature is gauged down to the very degree, your finely wrought egg custard, this centerpiece to your fancy dinner party or Thanksgiving spread, may just emerge from the oven sporting deep and craggy cracks right down its center. What the heck? What the water bath is more like it. When it comes to smooth, creamy custards and cheesecakes, a pan of hot water can make all the difference.
Cooking egg custards requires a very careful control of temperature. It isn’t enough to make sure your oven is accurate. Sometimes it isn’t even enough to simply keep your oven temperature low. When exposed to high heat, egg proteins will coagulate rapidly, forming strong bonds with other nearby proteins, clumping and lumping and pulling away from the liquid surrounding them. This is called curdling. It is the enemy of silky cheesecakes.
Left: Gentle heat and careful cooking keep the network of egg proteins loose and smooth. Right: High heat and fast cooking can cause egg proteins to clump together and pull apart.
In the test kitchen, our cooks combat the clumping, lumping, and pulling apart caused by curdling in custardlike desserts by cooking low and slow. After all, in the presence of unmitigated heat, not only will the egg proteins clump and pull apart but the edges of a cheesecake will cook much faster than the center, too—neither a good thing.
A water bath (also known as a bain-marie) is another way. In this case, the cheesecake’s springform pan is placed in a roasting pan that is filled with water. Because the water never reaches a temperature higher than that of boiling water, or 212 degrees, the water slows down the cooking of the cake. The even, gentle heat moderates the temperature around the perimeter of the pan, preventing overheating (and overcooking) around the edges. At least in theory.
When associate editor Dan Souza went to test this, he knew exactly how to begin: Bake some cakes.
Dan made two identical cheesecakes and baked one directly on the oven rack and the other in a water bath, both in a 325-degree oven. He removed them when their centers reached 147 degrees.
Guess which one cracked?
The cake that was baked in a water bath was even-colored and smooth (below, left). The other cake finished up overly browned and marred with some deep cracks in its center (below, right).
Dan also took the temperature of the cakes in the center, middle and outer edge.
After pulling them out of the oven, Dan found that the cake baked in a water bath was 178 degrees at the edge.
The cake baked straight on the rack clocked in at nearly 214 degrees… a definitive, disappointingly overcooked dessert.
In conclusion? When making egg custardy desserts here in the test kitchen, we often use a water bath, and you should, too. It provides the even, gentle heat needed to produce a silky, smooth cheesecake from center to edge. Not to mention: The considerable moisture added to the oven (more than 4 cups of water evaporated from the bath during cooking) helps to keep the top of the cake supple, discouraging cracking.
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Our recipe for Spiced Pumpkin Cheesecake is free through December 3, 2012.
Got any custardy questions? Leave 'em in the comments.