Pizza Cooking Explained Scientifically: 3 Physical Processes for The Perfect Pizza

We see it piping hot on the plate, ready to bite into it, and we don't even think about it, caught up in the heat of the moment: but cooking pizza is one of the most fascinating and complicated processes in Italian cuisine. Let's immediately dispel the myth of the wood-fired oven: with two perfectly made pizzas in front of us, it's almost impossible to distinguish which one is cooked in an electric oven and which in a wood-fired oven. Cooking pizza is a scientifically difficult process, but the fuel used to create the heat has nothing to do with it. If for so long we were forced to use a wood-fired oven for Neapolitan pizza, it was only because we needed an enormous amount of heat that only the Neapolitan oven and wood combustion could provide. Today, this is no longer the case: we have high-end gas and electric ovens, which easily reach 930°F/500°C. But if pizza isn't cooked with fuel, what kind of process does it undergo? Let's find out together.

The Three Principles of Pizza Cooking

It's not the fuel that makes pizza cooking perfect. So we can use wood, electricity, or gas without distinction. Pizza is cooked thanks to three different heat transfer methods:

1. The first is thermal conduction: according to the second law of thermodynamics, there is an exchange of heat between a hotter body, in this case the base on which the pizza rests, and a colder body, namely the pizza. When we bring two bodies with different temperatures into contact, there is an immediate heat exchange between the point of contact (the base of the oven in this case) and the pizza, which changes its temperature abruptly. The dough goes from its 68°F/20°C temperature to the 840-896°F/450-480°C of the oven brick. The point of contact therefore reaches a temperature of approximately 528°F/275°C. This point is called the "interface temperature" and is very important for the perfect cooking of our pizza: if the pizza chef is not careful and, after lifting it to check the cooking status of the base, places it in another part of the oven that is therefore hotter, the pizza will burn. This mistake is very common because it's so easy to make, and we can see it by lifting the pizza on our plate: if we see a "black curve" between the crust and the center of the pizza, the product was moved in the oven carelessly. Over time, the temperature of the pizza changes naturally thanks to conduction: to cook the pizza, the interior must be dehydrated, with water vapor replaced by heat. This occurs at a temperature of 212°F/100°C. Neapolitan pizzas are about 6 millimeters thick, which means they take at least 60 seconds to cook. Traditionally, Neapolitan pizza cooks in 90 seconds. Conduction is certainly the most important phenomenon in determining the exact doneness of the pizza.
2. The second principle that determines how pizza cooks is thermal radiation: in the oven, many hot electromagnetic waves are formed that cook the pizza from above. So, yes, you understood correctly: pizza cooks thanks to radiation. Obviously, we're not in Chernobyl: there are many types of radiation. In reality, we experience this specific principle firsthand every winter, because it's the same physical concept as electric heaters or fireplaces. If we place our hand near a heat source, it heats up thanks to thermal radiation, sometimes to the point of burning us. In an oven, these waves are much more numerous and can cook a pizza. The intensity of thermal radiation is calculated based on the amount of energy released on each square meter of surface. The law that determines all this is called the Stefan-Boltzmann Law and is visible to the naked eye thanks to shades of red (like gas and wood fires, or electrical resistors). The interesting thing is that this infrared radiation is ambivalent: it is produced by the oven towards the pizza, but the pizza also produces it towards the heat source. This exchange of radiation allows our leavened product to reach the ideal temperature, in the right amount of time.
3. The last principle is the least relevant: we're talking about thermal convection, caused by the recycling of air. Air moves in a circle in the oven and heats the pizza when it comes into contact with it. The heat has a "weight," which is released onto the pizza, so the cooler air is lighter and rises, heating up again and "falling" back onto the pizza. These movements are called  "convective motions." We often see this phenomenon in reality: it's the same as boiling water. The heat from the fire under the pot heats the cold water at the base and rises, bringing it to a boil, creating a circular motion. In the oven, the same thing happens, but with air: the airflow creates a sort of wind that cooks the pizza. In physics, water and air undergo the same processes because they are "fluids," that is, materials without a shape of their own.

We know all this thanks to three scientists, Andrey Varlamov, Andreas Glatz, and Sergio Grasso, who in 2018 published a study: "The Physics of Baking a Good Pizza," intrigued by all these processes that are evident and fascinating to the expert eye. In Italy, they have also seen a similar study, focusing on the entire process that leads to the creation of the product, from dough to baking, and was conducted by Enzo Coccia, one of the best pizza chefs in the world, together with Professor Paolo Masi, one of the most important chemical engineers in the country; a professor for years at the Federico II University in the Faculty of Food Science and Technology, he led to the creation of "La Pizza Napoletana," a small, fundamental volume in the history of pizza. Here we also find the empirical debunking of the "wood aromas" given off by the oven: complete with boards of different woods, he explained how each of them, burning in different ways and for different times, has different effects on the cooking but certainly not on the flavor of the pizza, challenging anyone to distinguish the aromas of beech from oak. Wood doesn't add any flavor to pizza. It only provides energy: wood doesn't burn, it's just charcoal, ideal for maintaining a constant temperature. These five brilliant minds explained to us how to cook a pizza from a scientific perspective.