Even though pizza stones and steels all seem the same—just a slab of material that gets hot—a number of factors can affect how well they perform. Here’s what we considered as we searched for the best ones:
Stone vs. steel
With the exception of a couple of models—one glazed stoneware and one made from a proprietary ceramic mix—we mainly focused on baking stones made from unglazed cordierite ceramic, and baking steels. Cordierite ceramic, a material commonly used in commercial bakery ovens, is great for baking stones because, as William Carty told us, “It’s rather insensitive to rapid changes in temperature” (so it won’t crack when you drop a cool piece of dough on the hot surface).
Ceramic stones are great for baking not only pizza and bread but also biscuits, scones, and tarts. Compared with steel, ceramic transfers heat more moderately and won’t torch the bottoms of delicate baked goods. Susan Reid, editor for Sift Magazine, bakes a lot on her stone: “Ninety percent of the time it lives in the oven on the middle shelf. I like baking pies on it. The ‘oomph’ of bottom heat helps keep the bottom crust from getting soggy.” (Note: Use only ceramic or metal pie plates. The hot stone could cause glass plates to shatter due to thermal shock.)
Baking steels, which are made from solid steel, deliver much more intense heat than ceramic. Scott Misture, professor of materials science, explained “The heat conduction in the steel is probably 100, 200, or 300 times faster … so that’s a dramatic difference”.
At ¼ to ½ inch thick, baking steels are also much thicker than a baking sheet or even a cast-iron pan, and therefore they hold a lot more heat. Ultra-thin-crust pizzas, like New York- and Neapolitan-style pies, bake very well on steel because the intense blast of heat is crucial to get proper browning and oven spring in a short amount of time. But steel heat is too intense for buttery pastries, as proven by a batch of black-bottomed croissants. The steel also scorched the bottoms of the bread we baked.
Size and shape
Size options are almost as important as what a baking stone or steel is made from, because ovens vary. You want as big a baking surface as possible, while still allowing for some airflow around your stone.
Rectangular stones are more versatile than round ones. A batch of baguettes or a baking sheet will fit on a rectangle. But on a 14-inch diameter circle? Not so easy. Even if you’re just interested in making pizza, you want as much surface area as possible to rotate and scoot the pie around so it bakes evenly. That said, if you have a tiny oven and your only option is a round stone, that’s fine. It’s better than nothing!
If you want a rectangular stone, make sure you get the right size baking stone or steel for your oven. Ovens and stones both vary, but a 30-inch stove should fit a 15-by-20-inch stone. Just make sure there’s a 1-inch gap between the stone and the oven walls on all sides, because it’s crucial for airflow in the oven. Good air circulation not only promotes even baking but also boosts your oven’s longevity and performance. If too much heat is trapped in the lower part of the oven, you run the risk of damaging electronic parts, like a gas oven ignition unit.
There’s a sweet spot when it comes to stone and steel thickness. If it’s too thin, it won’t hold enough heat, especially for baking back-to-back pizzas. Too thick and it’ll take longer than two hours to preheat (and be more unwieldy to move). Depending on the season, that means that by the time the stone is ready, you could be stretching dough in an unbearably hot kitchen. We found the ideal thickness for stone to be ½ to ¾ inch, and ⅜ inch for steel.
A top-performing baking stone or steel is a hefty piece of cookware. If you’re worried about lifting your creations, stone is a good choice because it weighs significantly less than steel.
In our testing, we found that pizzas baked on stones with coarser surfaces were much browner, crisper, and puffier than ones we made on smoother stones. The pizza we made on a glazed stone turned out surprisingly golden, but the crust was limp and had the mouthfeel of a steamed bun. These results led us to theorize that surface texture affects the crust’s quality and texture. When we asked Carty, he agreed that our theory is plausible, saying, “A pizza dough that’s wet is going to have a tendency to adhere well to that smoother stone rather than a rougher stone. A rougher stone is going to create air pockets.” A craggier surface also creates pathways for steam to escape from under the dough.
Surface texture of a baking steel probably isn’t as important since it has higher conductivity than ceramic. But the baking steels we tested, while not as rough as our favorite stones, do have the coarse texture of a Lodge cast-iron skillet.