The Pizza Lab: In Which We Get The KettlePizza Insert Working And Meet Its Maker

J. Kenji Lopez-Alt

Good news: we finally got some good results out of the KettlePizza after-market insert that supposedly turns your kettle grill into a wood-burning pizza oven. Strike that, we actually got great results. In fact, I'd even say the pies I've been pulling off my grill for the past few weeks have been some of the best I've ever made at home.

But hold up, what's going on? Haven't we already reviewed the original insert along with the new and improved model and achieved only mediocre-to-poor results?

Yes indeed. But those tests were on the KettlePizza insert, straight-out-of-the-box, no hacking no modifying, working with them exactly as instructed. This time, we've tried out a few different inexpensive hacks to modify the existing insert into something that really produces a great pie. By the time we were through, we were pulling out neapolitan-style pies that cooked through in a mere two to three minutes, producing excellent charring, a moist, cloud-like interior, and a crackly, blistered crust.

The Problems With the Original

Here's what the insert looks like out of the box:


A steel ring with a door cut in it, and a stone that you place on your grill rack. That's it. The problem here is that when you bake your pizzas, even with an air temperature over nearly 1000°F, the tops of the pies don't cook nearly fast enough. You end up with something charred on the bottom but barely pale blond on top.

Now for some people, this isn't a big deal. We visited the KettlePizza inventor Al Contarino at his small warehouse-style factory just north of Boston and chatted with him about his goals and his market. "Most of our customers are dads who just want to cook a few pizzas with the kids in the backyard. They aren't the hardcore pizza guys, they're happy just to get decent results."

That makes a lot of sense, and by all accounts, those casual pizza-making customers are very happy with the results.

That said, I wondered if we couldn't right the thing up to work for you guys, the Slice'rs and real pie-heads.

I had two theories as to why the top of the pizzas aren't cooking fast enough. The first is that there is too much volume in the grill once the insert is placed and the domed lid is in place. Air circulates around the top, up and over the pie, then goes straight out the door in the front. Your pizza ends up missing the bulk of the hot air.

The second theory is that a kettle grill lid is simply too thin and conductive. Rather than storing heat and re-emitting it as radiant energy the way a real stone oven does, heat is conducted then radiated outwards into the air. Your pizza doesn't get enough radiation, and thus doesn't cook fast enough.

Testing Theory #1

Theory 1 is easy to test. If it's simply a matter of air volume, reducing that headspace should make for a superior end product. To test this, I covered the entire top surface of the KettlePizza insert with heavy duty aluminum foil before placing the lid on it to keep it in place.

After firing it up and preheating, I baked off a pie. After about 5 minutes, here's what emerged from the oven:


A definite and huge improvement, but still not quite the bumpy, blistery, charred look I was going for. Looks like the thermal mass issue would have to be addressed.

Testing Theory #2

KettlePizza inventor Al is a clever man and designed his gadget to be used not just as a pizza oven, but also as a "double cooker," allowing you to grill foods on two different levels simultaneously, which he demonstrates in this video. The idea is that you put your chicken or steak or whatever on the bottom grill close to the coals, then insert a second grill (you can get them for under $20 on Amazon) where you can slowly cook your corn or other vegetables.

What I saw was an opportunity to solve the thermal mass problem.


I set up the KettlePizza with a stone on the bottom, a second grate, and a large stone on the top (Ideally I would have like a completely circular one to cover the entire top surface), then sealed up all the edges with heavy duty aluminum foil and lit'er up.


After about 20 minutes of preheating, I hit temperatures that seemed reasonable for pizza: a little over 500°F on the floor (which actually rose up to around 650°F by the time I was on my third pie), and nearly 800°F on the top stone, with air temps somewhere in the 800 to 900°F range.


For this particular test, I didn't go straight for a traditional Neapolitan style, but instead did a sort of hybrid mix of a Neapolitan with a New York style pizza, using a no-knead, cold fermented Neapolitan dough, along with a cooked New York style pizza sauce and some aged, full-fat, shredded mozzarella.

J. Kenji Lopez-Alt

I knew I was in good shape when I made my first turn after 45 seconds and saw the great charring on the bones.

Here's what popped out about 4 minutes later:


Neapolitan? No. I'd compare it in flavor more to the smoky, New York style pies you can get at Best Pizza in Williamsburg, though mine definitely had much more charring and a lighter, poofier crust.

I mean, check out this cornicione:


As the grill continued to heat up, the pies became increasingly better, cooking faster and faster. They peaked at about 2 minutes before the coals started to lose some of their heat. I'd imagine that the heat from the dying coals would be perfect for cooking some rustic Italian or French-style bread.


My favorite pie of the night was made with pepperoni (unfortunately no natural casing, though they still managed to get some nice charred, crisp edges), along with some homemade sausage (using my recipe here) which I threw on in raw chunks lightly dusted in flour for easier application and better browning.


As for the bottom of the pies, they were coming out gorgeously crusty and charred:


This is a method I'll definitely be using in the future, and once you've actually got the KettlePizza insert, remarkably simple and inexpensive to throw together—far easier than some of the other hacks I've seen out there.

Though I do think I'm going to have to invest in a more heavy duty stone:


Would You Buy This?

After chatting with Al a bit longer, we got the idea perhaps there's a market in the pro-pizza audience for a Special Edition KettlePizza Insert aimed directly at the type of people who want to be able to cook at near Neapolitan speeds in their backyards. Right now, your only real options are to hack something together (and thus far this seems to be the cheapest and easiest gadget to hack), or go all out and build yourself a real pizza oven.


So my question to you guys is: If you could buy something that allowed you to convert your kettle grill into a hardcore pizza oven, right out of the box, no hacking required, for the fraction of a cost of a real pizza oven, would you want it?


Who knows—if there's enough support for the idea, it may become a reality some time in the future. Until then, I think I've finally come around and been convinced: With some minimal hacking, the KettlePizza Insert is a great solution for home pizza makers wishing to produce stone-oven quality pizza at home.