Making baked cheesecake is much more challenging than preparing the non-baked type. The oven temperatures have to be accurate and the baking and resting times well controlled. Another key to impeccable cheesecake is placing the baking pan in a water bath, a step that adds gentleness to the baking process and greatly reduces the chances the cheesecake will crack, curdle or turn dark.
Water Bath Concept
Baked foods like custards, soufflés and cheesecakes that contain high concentrations of dairy products and eggs tend to curdle if they cook too quickly. Placing the baking pan or dish into a pan of water in the oven insulates the pan from direct heat on the sides. The water bath temperature never exceeds 212 degrees F, the boiling point, because the water evaporates and turns into steam in an open pan, regardless of the oven temperature. Though maintaining a constant and relatively low temperature on all sides of the pan, the water bath lets the food cook evenly, maintain its silky texture and ensure the center gets done without overcooking the sides.
Choose a bath pan large enough to leave 2 to 3 inches between the edge of the cheesecake pan and the outer rim and at least as tall as your cheesecake pan. For example, if your cheesecake pan is 9 inches in diameter and 4 inches tall, the bath pan should be 11 to 12 inches in diameter and at least 4 inches high. You need enough room in the pan for the water to circulate and to easily add more water if necessary without splashing any on the cheesecake.
Water Bath Set-up
Adjust the oven rack to the middle position and preheat the oven to the desired temperature. When the oven is hot, pull out the rack and place the water bath pan on the middle. Place the filled cheesecake pan in center of the bath pan. If you use a springform pan, wrap the exterior bottom and sides with heavy-duty foil to deter water seepage into the cheesecake. Seepage is hard to prevent, so many cooks choose to use a regular pan for water bath baking. Carefully pour very hot tap water or boiling water into the bottom pan until it comes a little over halfway up the sides of the cheesecake pan. Gently slide the rack back into the oven and close the door.
Periodically check the water bath and replenish it with more hot water if it dips below 2 inches, but leave the cheesecake as undisturbed as possible while it bakes. When it has cooked for the prescribed time, immediately remove it from the water bath to prevent overcooking. It will look undercooked but will continue cooking as it cools, so do not cook it longer than recommended. Let it cool uninterrupted and completely on a rack and then cover and chill it for a minimum of 4 hours or overnight before serving.