The baking process causes the batter to expand and go from a liquid to a solid foam. The proteins will not start to denature until the temperature reaches around . During this rise in temperature the air bubbles will either expand, coalesce, or break. An egg white foam will continue to expand uniformly until the internal temperature reaches – . Based on the ideal gas law, as the temperature increases, the volume of the air bubbles will expand. The temperature will continue to rise, causing the cake to expand at different rates and egg white proteins will gradually denature. Some of the egg white proteins will start to denature and coagulate at around  . This establishes the setting of the foam structure. By the time the temperature reaches , all of the egg white proteins will have set in place.