Meredith asked via email:
"Hi there, I heard you on Wendy's podcast and I have a quick question. One of my favorite things to do is to bake cheesecakes. I have been reading different things about the best way to bake them. I have read that water baths are the best way. What are your thoughts on this, and how to bake a great cheesecake as well as a basic cheesecake that you can add your own flavors to?"
A cheesecake is a type of baked custard pie, like a flan or quiche or crème brûlée. A custard is a dish that is thickened with eggs, which are one of nature's most versatile and interesting ingredients.
The basic idea behind a custard is to use the proteins in the egg to act as a thickener, which means you blend the egg with dairy of various types, flavor the mixture, and heat it up. As the heat rises, the egg proteins become more rigid. the cream and flavorings are held in place by the rigid egg proteins, and you have one of the better desserts that mankind has invented.
There are two major concerns to keep in mind with eggs. The first is that you don't want to heat them up to too high of a temperature. The second is that you don't want to heat them up too quickly. Either will cause the proteins mentioned earlier to tighten up too much, which will cause no end of texture problems with your cheesecake (or any of your other custards).
The favorite way of combatting both problems in baked custards is a bain-marie, or water bath, around the custard container. As people who watch pots surely know, water takes a while to heat, so the water bath keeps your custard from heating up too quickly just from acting as an insulating barrier around your baked treat.
The other aspect to water slowing down the baking is that ovens work mostly by radiant heat, which is how sunlight heats things. The heat from the oven would normally travel straight from the heating element to the side of the pan, where the side of the pan heats up and sends its heat through to the custard. With direct radiant heat, the edges will get warm much faster than the center, so you can overcook your edges before the center is done.
When you put the water in the way, the water absorbs some of the radiant heat, and the container that the water is in absorbs even more of it. Then the container holding the water transfers its heat to the water, which transfers its heat to the cheesecake pan, then to the cheesecake. All of these layers of barriers slows down the heat transfer, ensuring a relatively even bake.
For the maximum temperature, the water helps there, as well. Water boils at 100°C/212°F. Well, usually. Even in a 350°F oven, whatever is touching the water is only really going to get up to around 212°F at most, which is a safe temperature for custards. So the water adds an extra layer of protection to the safety of your cheesecake as long as it's there.
As for recipes, Nicole Rees has a killer New York-Style Cheesecake calling for a water bath you could try, and as for customizing, Abby Dodge and Fine Cooking teamed up to create the Cheesecake Recipe Maker (do note that there's no water bath involved in recipes generated from the tool). Check it out, play with it, and make yourself a tasty cheesecake.