Air bubbles in pizza dough act like tiny ovens, cooking the crust from the inside out as they trap and expand steam.

Air bubbles in pizza dough form through yeast fermentation and gluten development. As yeast consumes sugars, it releases carbon dioxide gas, which becomes trapped within the elastic gluten network. When dough enters a high-heat oven—typically between 370°C and 480°C in traditional wood-fired settings—oven spring occurs.During the first few minutes of baking, the gas inside these pockets expands rapidly according to Charles's Law, which states that gas volume increases with temperature. Simultaneously, water in the dough evaporates into steam at 100°C. Because steam occupies roughly 1,600 times more space than liquid water, it exerts immense internal pressure on the bubble walls.This internal steam cooking is more efficient than the oven's dry heat because steam transfers thermal energy more effectively. This process ensures the dough's interior reaches safe temperatures quickly before the exterior burns. Research from institutions like the Modernist Cuisine lab shows that the size and distribution of these 'alveoli' (bubbles) determine the final texture and crumb structure of the pizza.The rapid expansion eventually stops as proteins in the flour denature and starches gelatinize, setting the crust's structure. This creates the characteristic charred 'leopard spotting' on the bubbles, where thin dough walls cook faster than the denser base. This delicate balance of heat and moisture is what separates a dense, heavy dough from a professional Neapolitan-style crust.