Unlike the convection oven in your kitchen that simply heats the air around your food, cob ovens use three forms of heat transfer: radiant heat from the walls, conduction heat from the floor, and hot air convected throughout the oven space. This creates a blisteringly hot steam that caramelizes the sugars on the outside of the loaf and forms a thick, chewy crust. After cooking your bread in a cob oven, the results from your kitchen oven will seem bland and dry.