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Pizzology [ˈpētsələjē] noun
1. The study of pizza, subdivided into many individual subfields that cover various aspects, such as dough rheology, cheese-flow structure, oven thermodynamics, sauce composition, gluten formation and expansion, and topping distribution pattern.
2. A new column at Slice about the science of pizzas.
We all know the drill, right? It's impossible to make restaurant-quality Neapolitan pizza at home. In order to achieve a crust that's tender and pillowy inside with charring on the undercarriage and leopard-spotting along the rim, you need a wood-burning oven with a floor temperature of at least 700°F, and a dome temperature of at least 1,000°F. Anything lower than that, and the crust dries out too much before it takes on color. A home oven maxes out at around 550°F, so barring breaking your thermostat or engaging in other such high-maintenance, obsessives-only style hacks, you're stuck. Perfect Neapolitan pizza at home is a myth. It's a golden ring that can be strived for but never quite achieved.
So where does that leave the rest of us home cooks? The ones who want to throw together a quick, really good pizza that doesn't require jury-rigging the oven? Lucky for us, really-really-good-but-not-quite-authentic-Neapolitan-pizza is not an unattainable goal.
My criteria are as follows:
- The pizza must have a flavorful crust that is charred both top and bottom, crisp with an airy, chewy crumb, and a significant cornicione (the poofy lip around the edge).
- The sauce and cheese must follow Neapolitan guidelines: fresh buffalo mozzarella or fior di latte, and an uncooked sauce of canned tomatoes and salt.
- I must be able to cook the whole thing without the use of specialized equipment, and without modifying or breaking the warranty on any of my existing equipment.
- I must be able to cook the whole thing indoors.
With these criteria in mind, I set to work.
First things first: the base. For a true Neapolitan style dough, these are by far the two most important ingredients:
A scale is absolutely essential. Measuring flour by volume is a crap shoot. Depending on how well packed it is, a cup can weigh anywhere from 4 ounces to 6 ounces. That's an increase of 50%. Yikes! Do yourself a favor: invest in a good kitchen scale. Your baking will improve immeasurably (or is it measurably?).
Italian Tipo "00" flour is the standard for Neapolitan pizza. Contrary to popular belief, it is not lower in protein than regular all-purpose flour. I don't know where this bad piece of misinformation started, but it probably has to do with the description of the flour as "soft"—a description which refers to its fine milling, not to its protein content. The flour actually comes in a variety of protein content levels, intended for various baking projects. Look for the high protein stuff in the red bag, which is comparable to American bread flour. Antimo Caputo makes the industry standard, and you can easily order it online in one kilogram bags. I order it in packs of ten, much to my wife's chagrin.
So what is the role of protein in the flour? Well, when it comes in contact with water and gets kneaded, the normally balled up protein molecules stretch out and link together, forming a stretchy matrix called gluten. It's this gluten that gives bread its structure. The higher the protein content, the stretchier the dough, the larger the bubbles and pockets it can form in the interior, and the greater the chew.
A basic Neapolitan pizza dough is simple: combine flour, water, salt, and yeast, knead it a bit, let it rise at least overnight, form it into balls, allow them to rise, stretch, and top. Taking the weight of the flour as 100%, I add 60% water, 2% salt, and 1% yeast. That breaks down to 10 ounces (2 cups) of flour, 6 ounces of water, 1 teaspoon of kosher salt, and a half teaspoon of yeast for around three pizza crusts.
So is that "00" flour really all it's cracked up to be? For my first test, I tried baking four pizzas side by side, using "00" flour, all-purpose flour, high protein bread flour, and a mixture of all-purpose and cake flour, as some recipes bafflingly recommend (most likely because the authors believe the myth that "00" is low protein). For now, I baked my pizzas on a preheated pizza stone in my oven, using a simple sauce of pureed canned San Marzano tomatoes, some local mozzarella, fresh basil, olive oil, and kosher salt.
As expected, the cake flour crust was a bust. Sure, it was crispy, but that's all there was to it. No interior structure, no chew, no good. The "00" flour, was best, with a super crisp exterior, and a soft, chewy center. Of the other two, high protein bread flour came in a close second, with A/P flour trailing just behind. My take? Order the fancy flour if you'd like (I'll still continue), but either bread or all-purpose American flours will do just fine.
On to the bigger problems: Proper browning.
The Crust of the Matter
Despite using a really hot oven and stone, my pies were simply taking too long to brown—around eight minutes. I wanted to cut down that cooking time to a maximum of two or three. My first thought was to add some baking soda to the dough to increase its pH, as browning reactions occur better in slightly basic environments. Unfortunately, I didn't take into account that gluten formation and yeast activity are also hindered by high pH. The dough barely rose at all, even overnight. Adding a touch of sugar turned out to be the best solution, increasing the browning on the crust slightly, and improving flavor and texture by giving the yeast a better food source. Cooking time was cut down to around 5 minutes. Better, but still not great.
And there was a bigger problem: Judging from this shot of the undercarriage, you'd think that these pizzas were pretty darn good.
But just like monkfish and Abbey Road, this pizza's got a much better bottom half than top half. The upper crust literally pales in comparison:
It's basic thermodynamics. Air at a given temperature has less energy than stone at a given temperature. Because of this, even if both my stone and the air in my oven are at 550 degrees, the part of the pizza in contact with the stone cooks much more rapidly than the top. By the time the bottom is crisp, the top has yet to take on any significant color.
The solution to this is quite simple, and happily makes for a much cooler kitchen as well: forget preheating the oven: just use the broiler. A broiler not only cooks via hot air like the oven, but more importantly, it adds a significant amount of radiant heat to the mix, cooking the top of the pizza directly with electro-magnetic waves—a much more efficient means of heat transfer.
I've tried all of the various hacks: using an overturned cast iron skillet under the broiler to simultaneously cook the top and bottom, using a stone/broiler combination, using a broiler/direct flame over the burner combination. In the end, the one that worked best was a simple skillet-to-broiler method, though it took a little finessing.
I preheated a skillet over high heat while I stretched out and topped my dough nearby on a cutting board. When it came time to slide the topped pizza into the skillet, I ran into problems: it's nearly impossible to get a topped pie into a slope-sided skillet without making a big mess of the matter. Better option: put the raw dough directly into the skillet and top it carefully directly in the pan.
After cooking for around a minute and a half, the bottom crust achieved the perfect degree of char—even better than what I was getting on the stone. Interestingly enough, the pan was actually cooler than the stone I was using, maxing out at around 450 degrees. So how does a 450 degree pan brown better and faster than a 550 degree stone? It's a matter of heat capacity and density.
The heat capacity of a material is directly related to the amount of energy that a given mass of material holds at a given temperature. Even though stone has almost twice the heat capacity than steel (.2 kcal/kg C vs. .1 kcal/kg C), it loses in two ways: it is far less dense than steel, and it has a much lower rate of heat conduction than steel. The pizza cooking in a skillet is not just getting energy from the pan—it's getting energy from the burner below the pan as it gets rapidly conducted through the metal.
It's a clear demonstration of how when cooking foods, what matters it the amount of energy transferred, not just the temperature you cook at. The two are often directly related, but not always.
Back to the pie: I slid the half-baked pizza, pan and all, under a preheated broiler, as close as I could get to the heat source. Thanks to the slightly sugared dough, the upper crust was charred within a matter of minutes, only requiring me to rotate it once midway through cooking. Things were looking good when I pulled it out.
As you can see, the crust is beautifully charred, the cheese has melted and just barely started to brown, and the basil has wilted and released its aroma to the pie.
I transferred it to a cutting board and sliced it with a pizza wheel, the crust giving a promising crackle as I made my way through it. Everything looked great until I took a look inside the cornicione. Rather than being puffed and airy, it had a denser, bread-like crumb. Not horrible, but not as good as I'd like it to be.
The problem is with oven spring (or a lack thereof). When a pizza (or any bread, for that matter) first gets blasted by the heat of an oven, the moist air pockets inside the dough rapidly heat and expand, causing the dough to puff out. If it expands rapidly enough, it's possible to get a serious amount of poofing before the proteins in the flour begin to set, locking those bubbles in place. So there are really three factors that affect it: the stretchiness of the gluten in the dough, the amount of air in the dough, and the efficiency of heat transfer in the oven. I didn't want to have to go back to the drawing board with my dough, so I focused on the latter two.
I figured that stretching more gently might help retain more of the air in the dough, and it helped a little—though not significantly. To be honest, even rolling the dough out with a rolling pin gave me nearly as much of a puffed crust as I got when gently stretching with my fingers.
The real issue was that by starting the pizza in a skillet, I was cooking it unilaterally from the bottom up. Even though the upper surface wasn't browning at all, the inner structure was still slowly getting heated in the skillet, causing it to firm up slightly. By the time I got my pizza to the broiler, the dough was too set to puff dramatically. I tried adding a lid to the pan during the stovetop cooking phase, hoping that it would capture some heat and help the crust puff up. Better, but still not great.
Then the simplicity of the real solution hit me: just reverse the darn order. I preheated a skillet, formed my pizza in it, and rather than waiting for the bottom to char, I immediately slid the whole thing under the broiler.
This time the cornicione rose, bubbled, and puffed beautifully. All that remained was to bang it back on the stovetop for a minute or two until the bottom crust was done, and it was good to go.
So is it as good as a real Neapolitan pizza fired in a wood burning oven? No way. Would I be happy, impressed, and completely satisfied if I went to my friends place and he served me this pie? Absolutely. And on top of that, it doesn't require you to preheat an oven, and the whole thing is cooked within a matter of minutes—a really big deal for me in an apartment that gets absurdly hot in the summer.
P.S. If you've got any contacts in the Vera Pizza Napoletana Association, please don't report me. I know what Italians do to people who bastardize their cuisine.