Burned Them Again!

Don’t worry, it’s happened to all of us.  You volunteered to bring the cookies because your grandmother had a great recipe.  You last made them years ago, but how hard could it be?  The first pan came out of the oven under-done; you adjusted the temperature.  The second pan came out over-done; you adjusted the time.  The third pan – well suffice it to say your attempts remained inconsistent.  You should have used a pizza stone!

Uniform heat distribution is the key.  A pizza or baking stone is a thick piece of circular stone, usually supported by metallic handles.  Its thickness and composition cause it to slowly build-up heat, resulting in a solid surface that is close to the same temperature at every point (except the very edge).  Metallic baking sheets start off uniform, but over time they distort or develop residue that changes how well they conduct heat from place to place.

Tips for using a baking stone:

• ONLY wash a baking stone with water – do not use soaps or scrubs.
• Never put a baking stone in the situation of changing temperature rapidly or unevenly, such as sending it directly from the oven to the sink. The stone will crack.
• Preheat the oven with the stone in it already. Many recipes will suggest preheating the stone for an hour before use, so it equilibrates with the temperature of the oven.  While this is true, I find it’s better for cookies to only preheat the stone for 5-10 minutes.

Let’s say we placed a hot pizza stone safely on a table, and topped it with an ice cube.  Assume, like good physicists do, that this is an ideal stone and doesn’t crack.  Our understanding of how heat works says heat will move from the hot stone to the cold ice cube, melting the ice.  However, if we approach heat transfer from the perspective of Statistical Mechanics we find something else – heat moving from hot objects to cold objects is a tendency.  That interpretation suggests that heat can move from the cold ice cube into the hot stone, just very, very, very unreliably.  You’d be surprised how much “likelihood” factors in to how the Universe works!