I’ve been really looking forward to sticking it to the piehead that wrote ‘radiation from the upper stone really isn’t a factor in baking a pizza’. I turns out that radiation is a big factor and I’ve got pictures to prove it. Unfortunately that piehead is me, but in the interest of pizza science and good fun, I’m not going to be denied.
The photos below show what happens if you load a stone-cold oven with Wonderbread, then, with rotisserie off, ignite the burner and wait one minute. Slices get pretty toasty near the flame and decrease in color from the flame toward the left-front of the oven. Note that the rear-left of the oven and forward center-to-right section of the oven do not show much browning, hence less heat flow. (It’s a good thing Blackstone added a rotisserie.) The overhead stone isn’t likely a factor here, since the stone starts out at ambient temperature and doesn’t heat up much in one minute’s time. Hence the dominant heat making toast is likely convection. Piehead expected that.
The last photo may be a surprise to some. In this, the second case, the oven was heated up full blast until the upper stone was 900F. Then the flame was snuffed out and a slice of bread was placed center stone. One minute later, that slice is pretty toasty as well. Piehead didn’t see that coming.
I think this is a reasonable way to visualize what is happening inside a standard, unmodified Blackstone oven. One can assume that the combination of flame-thrower convection, and overhead radiation, work together to cook a pie in short order. Comparing the center-most slice during convection to the lone slice subject to radiation, one might say that the coloration is comparable. As a rule-of-thumb, it seems that both modes of heat transfer contribute somewhat equally in baking the pie.