Baking in a water bath may seem like an unnecessary step, but this easy cooking method is your best insurance against curdled custards and cracked cheesecakes. These desserts are thickened primarily by egg proteins, which set well below 212°F. Unless these proteins are protected from the high heat of the oven, they’ll overcook and tighten or shrink, causing your custard to crack or separate into curdled egg and liquid. A water bath insulates custards from the direct heat of the oven because the water can’t exceed 212°F, unlike the air in a 350°F oven. Without a water bath, the outside of your dessert would overcook before the center is done. And direct heat could take small custards, like pudding cakes, from cooked to cracked within a minute. But if they’re in a water bath, you have more time to catch them at the perfect degree of doneness.