cheesecake help

[Crickets]

Can anyone tell me why a cheesecake would crack on top?
My niece made a sweet potato cheesecake and her recipe told her how long to cook it and then she was told to cut the oven off and leave the cake in there four hours and then place it directly in the refrigerator,which she did but the cake cracked on top before she took it out of the oven.
Can you help me??

Thanks,
Cricket

[truleelee]

I looked it up and found these two reasons:

1. Using the paddle attachment of an electric mixer works best to mix the ingredients. Regular whipping beaters add too much air to the mixture creating a less creamy texture, and may also contribute to cracks in the finished cheesecake. If you must use regular whipping beaters, set the mixer to low for a minimal amount of air in your cake.
2. Even if you follow all the directions carefully, you may still develop cracks on top of the finished cheesecake. These cracks are caused by steam escaping. Too much steam escaping too fast causes these cracks. Extreme temperature changes will also crack the top of the cake. That is why cheesecake recipes call for a relatively low baking temperature. Sometimes there just isn't anything to do but accept them as part of the charm of real homemade cheesecakes
courtesy of http://www.lesleycooks.com/cheesecake.htm

~Lisa

[knightmoves]

I have never tried this, but a friend of mine who works in a pastry kitchen, says to cool the cheesecake in the oven. Cook it the length of time stated, turn the oven off, and leave the cheesecake in until the oven is cool.