The amount of heat reflected/absorbed between the two sides is trivially small.
Your particular choice of wording here makes me very curious: Do you mean that there really was a measurable difference (which was trivially small)?
Yup, the lab could tell a difference! Shiney side (so mill roller facing, as opposed to the dull side which faces the other layer of aluminum) was marginally more reflective, but I believe (and a former coworker also remembered it as) it was less than a tenth of a percent (<0.1% for the visual folks)
Anyone who says it affects cooking time or something is mistaken, I’d wager.
Any info on surface roughness? I’m thinking shiny side would be smoother and therefore less sticky, though I don’t know how much the passivation layer would affect it. Probably no where close to making a difference at the end of the day, but I’m curious.
Jokes on you.
I baked my casserole with the shiny side up and pulled it out at 59 minutes and 55 seconds, when it was supposed to go for an hour.
So take that Dull Side!
