How heat gets into a pizza

Short answer

A pizza is cooked from below mainly by conduction from the surface it sits on, and from above mainly by radiation from hot oven walls, domes, flames or elements, with hot air (convection) contributing to both. A steel transfers heat into the base faster than a stone at the same temperature because steel conducts heat far better, and a domestic oven struggles mainly because it cannot get its top heat anywhere near as intense as a pizza oven's.

Three ways heat moves

Conduction is heat flowing through direct contact: the base of the pizza touching a hot stone, steel or tray. Convection is heat carried by moving air or gas — the hot air circulating in an oven, more vigorous with a fan. Radiation is heat travelling as infrared energy from any hot surface to anything cooler that it can 'see': the glowing dome of a wood-fired oven, a flame rolling across the ceiling of a gas oven, or a grill element.

Radiation increases very steeply with temperature — physically it scales with the fourth power of absolute temperature — so a surface at around 450 °C radiates several times more energy than one at around 250 °C, not just somewhat more. That is the main reason pizza ovens can cook the top of a pizza in a minute or two while a domestic oven takes many minutes.

Thermal mass versus conductivity

Two properties of a baking surface matter, and they are easily confused. Thermal mass (heat capacity) is how much heat the surface stores, which determines how far its temperature drops when a cold dough lands on it, and so how much it has to make up between pizzas. Conductivity is how quickly it can move that heat to the point of contact — and, between bakes, how quickly heat from the oven can work back into it.

Steel conducts heat roughly an order of magnitude better than the cordierite or clay of a typical baking stone, and per unit volume it also stores roughly twice as much heat. So at the same oven temperature, a steel pushes heat into the base faster: the underside sets and browns sooner, which is why many people find a steel at domestic temperatures behaves a bit like a stone at a higher temperature. The flip side is that a steel can burn a base in a very hot oven where a stone would not, and that a thin steel holds less heat in total than a thick one.

A stone hands heat over more gently and evenly. That suits very hot ovens and longer bakes where a steel's speed would scorch the base before the top is done. The sensory guide on steel and stone texture covers how the difference feels to eat.

Top–bottom balance

A good pizza needs the base and the top to finish at the same time. If the floor delivers heat faster than the top, the base chars while the cheese is still pale; if the top is faster, the cheese browns over a soft, pale base. Pizza ovens are built so that floor and dome are both very hot and roughly balanced for their style — a Neapolitan oven typically runs its floor somewhat cooler than its dome so that the base does not burn during a bake of around a minute or so.

In a domestic oven, the bottom is usually the easier half: a preheated stone or steel on a low or middle shelf can deliver plenty of conductive heat. The top is harder, because a domestic oven's walls are only around 250–300 °C at best and its top element cycles on and off. Using the grill (broiler) for part of the bake, or placing the surface closer to the top element, adds radiant heat from above and helps rebalance it.

Why domestic ovens struggle — and what they can do

The limitation is mostly temperature, and therefore radiation. A wood-fired or gas pizza oven commonly runs its interior at roughly 400–500 °C, so the top cooks fast enough to match a very short bake. A domestic oven at its maximum cannot radiate that much heat, so bakes are longer, the dough dries more before it sets, and the characteristic fast-baked texture is hard to reproduce.

That does not make a domestic oven useless; it makes it suited to styles designed for lower temperatures and longer bakes, such as New York-style or pan pizzas. A long preheat (often 45–60 minutes for a stone or steel to reach temperature), a conductive surface and the grill used deliberately close much of the gap, but not all of it.

Common misconceptions

“A steel is better because it gets hotter than a stone.”

In the same oven both reach roughly the same temperature. The steel delivers that heat into the dough faster because it conducts better; the surface temperature is not what differs.

“Oven temperature is the only number that matters.”

How heat arrives matters as much as the dial setting. A stone, a steel and a thin tray at the same oven temperature cook a base very differently, and top heat depends on radiant sources the dial does not describe.

“A fan oven always makes better pizza.”

Convection speeds up heat transfer from the air, which can help browning on top, but it does little for the base and can dry the surface. Whether it helps depends on the style and the oven.

What this page cannot tell you

Temperatures given are approximate and vary widely between ovens, models and how they are fired; oven thermostats often read differently from the actual surface temperature. This page does not give exact conductivity figures for particular products, and PizzaHQ has not measured any oven or baking surface.

Related

Evidence

• On Food and Cooking: The Science and Lore of the Kitchen (revised edition) — Scribner
• Modernist Pizza — The Cooking Lab
• How to Get Your Pizza Stone to Heat More Evenly — America's Test Kitchen
• The Most Common Baking Steel Mistakes (and How to Avoid Them) — Scratch Made Pizza
• Pizzeria-quality pizza in the home oven? Find how. — Alfa Forni