Former process engineer in an aluminum factory. Aluminum foil is only shiny on one side and duller on the other for process reasons, not for any “turn this part towards baking, etc” reasons.
It’s just easier to double it on itself and machine it to double thickness than it is to hit single thickness precision, especially given how much more tensile strength it gives it.
Also, our QA lab did all kinds of tests on it to settle arguments. The amount of heat reflected/absorbed between the two sides is trivially small. But if you like one side better you should wrap it that way, for sure!
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.
Former process engineer in an aluminum factory. Aluminum foil is only shiny on one side and duller on the other for process reasons, not for any “turn this part towards baking, etc” reasons.
It’s just easier to double it on itself and machine it to double thickness than it is to hit single thickness precision, especially given how much more tensile strength it gives it.
Also, our QA lab did all kinds of tests on it to settle arguments. The amount of heat reflected/absorbed between the two sides is trivially small. But if you like one side better you should wrap it that way, for sure!
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.
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!
Welcome to the Dull Side.