Better crust starts with what's under it.

Every guide in this category says it tested a dozen stones. Some of them describe six-week protocols and sixty pizzas, and then publish no photographs, no per-unit data, no temperature logs and no named tester. We have not baked on any of these products, and we would rather say that plainly than join in.

What we do instead: compile every published specification we can source and cite each one to the page it came from. Compute the thermal numbers - preheat curves, stored energy, effusivity - from published material constants, and show the working so you can re-run it on a calculator. Read the manufacturers' own manuals rather than paraphrasing what somebody else said about them. And where a maker publishes nothing, say so on the page instead of filling the gap with a number we invented.

That approach produced findings the rest of this category does not have. Carbon steel's thermal effusivity is 8.5 times cordierite's - not the 18 times you will read everywhere, which is a conductivity-shaped number being reused to describe stored energy. A quarter-inch steel is slower to preheat than a 16-inch stone, because the bottleneck is mass rather than conduction. And bakeware cordierite works out about 20 percent less dense than the textbook figure, which we only know because two makers published a weight alongside their dimensions.

The full method, the constants table and a worked example are here, including everything we assumed rather than measured.