So why do pizza stones work? What makes a stone good to use when baking? Will it really make that much of a difference?
The advantages of using a pizza stone are:
The best surface to bake bread on is a flat hot stone. Instead of relying on the inefficient process of indirect heat transfer- from oven wall to warm air to bread- a loaf placed on a hot stone quickly heats up by direct conduction. Leading to a crisp bottom crust and often deep flavors. Everything from pizza beehive ovens to a tandoor clay pots relies on the magic of direct heat. In addition, the intense heat from the porous surface pulls moisture from the outside of dough to create a perfectly crunchy crust.
The density of the stone causes it to retain and spread heat even throughout itself. It typically takes 30 - 45 minutes to heat the stone to temperature, but once it's at temperature, it retains that heat for a good long while. Additionally, the heat is evenly dispersed over the surface of the stone. Less dense cooking pans aren't as reliable for evenly dispersing heat.
While an oven stays on during cooking, the temperature within the oven fluctuates. When heating an oven to a set temperature, the oven continues to heat until it reaches the temperature, then stops heating to sit at the desired temperature. Once the stove detects that the temperature is below the desired temp, it turns back on to heat back to the desired temperature. When cooking with a baking stone, the stone will act as a stabilizing element of heat, normalizing the cool-down that occurs when the oven stops heating. Additionally, when the stove does turn on to heat itself, it reheats at a more even rate than without using the stone.
These factors are what make a cooking stone unique and best way to mimic the conditions of a brick oven.