Thanks Craig for bringing this up. I've always accepted the myth without thinking. I will eagerly await the next episode of Pizza Myth busters. In fact, I would love to see it get its own tab on the forum. I think there's a TON of fodder for future episodes (Blind taste test: Are San Marzanos really the best?, How helpful is Autolyzing?)
I'm wondering though, what if you MADE the stone porous enough for steam to escape? What if you drilled holes in it? Would the steam travel down? We know from bubbles that it's down there. You would certainly lose heat retaining mass, but would there be a compensating benefit? Would there be a sweet spot? 1/2" steel would be a great one to try this out on, as there is already SO much mass to begin with.
On testing the sourdough myth: Does anyone know if you can see the difference between different strains of yeast with a reasonably priced microscope? This would make some aspects of testing the myth easier.
I read an article in Popular Science a few years ago. Someone in Germany had the idea of genetically modifying plaque forming bacteria so it generates alcohol (miniscule amounts) instead of plaque. They did it and decided to test it on themselves (beginning of a zombie movie). It didn't work. The modified strain was immediately killed by stronger bacteria in the guy's mouth.
He proceeded to get hundreds of samples of saliva. He used the samples to have petri dish cage matches (Two Bugs Enter. One Bug Leaves!").
Long story short, the author of the article claimed the guy hasn't brushed his teeth or gotten a cavity in months. Could you do the same sort of experiment with starters?