The thing that’s so surprising (and a little disconcerting) about Neapolitan pizza Margherita (which is what I made yesterday) is its simplicity. The crust is made of flour, yeast, water and salt. The sauce, crushed tomatoes and salt. The topping, herbs and a few pieces of fresh mozzarella. The big “ingredient” in a true Neapolitan pizza is the oven.
Why is the type of oven so important? All ovens get hot don’t they? Yes they do, but at the risk of sounding like a geek (though I clearly am one) there are several types of heat. Or rather I should say heat transfer, and they make a big difference in baking, especially Neapolitan pizzas.
Conventional home ovens work by a combination of radiant heat and convection. Think of radiant heat like a flashlight, focusing heat energy on food. Think of convection like moving water, bringing hot molecules into steady contact with it. Most home ovens are big metal boxes with some sort of heating element underneath, either gas or electric. When they’re turned on heat begins to radiate up from the floor and warm the oven’s contents. At the same time currents of hot air begin to circulate and collide with them (a convection oven heightens this effect by employing a circulating fan).
The trouble is that a conventional oven is not a particularly intense heating environment, at least by brick oven standards. The radiant heat it emits only comes from one direction, and moving currents of hot air have minimal effect on a pizza (moving currents of hot oil would be another matter entirely, see pizza puffs).
A brick oven is a completely different beast. It’s all about the Big Heat. Brick ovens come in two kinds. So-called “black” ovens in which fires are lit directly on the oven floor and left to burn for several hours before being brushed aside (a process that covers the inside and outside front with soot), and “white” ovens that have a separate fire box, usually directly underneath the baking area. Black ovens use only wood (because of coal residues), while white ovens can employ either coal or wood. Both have thick brick and masonry walls and low ceilings. Of the two, the black oven is best for pizza.
Why? Because over the hours, as the wood fire burns in a “black” brick oven, the thick walls and low, domed ceiling are soaking up ever increasing amounts of heat. Once the fire is put out or dies down, those surfaces start radiating all that heat back out again, creating a baking environment of between 800 and 900 degrees. Yet it’s not just sheer temperature that makes a brick oven so special. It’s the fact that it gives off intense, radiant heat from all directions, blasting that thin little round of dough into a crispy, charred and ready-to-eat Neapolitan pie in about 90 seconds.
Of course not everybody has one of these. Even the famed Gennaro Lombardi, the father of American pizza, remarked that his pizzas emerged from his coal-fired “white” brick oven a little on the, shall we say, limp side, when he opened his pizzeria in 1905. So he adapted his recipe, made the dough a little thicker and his pies a little bigger and better suited to lower temperatures. New Yorkers worship it to this day.