Which side of Reynolds Wrap® Aluminum Foil should I use, the shiny or the dull side?
Actually, it makes no difference which side of the aluminum foil you use—both sides do the same fine job of cooking, freezing and storing food. The difference in appearance between dull and shiny is due to the foil manufacturing process. In the final rolling step, two layers of foil are passed through the rolling mill at the same time. The side coming in contact with the mill's highly polished steel rollers becomes shiny. The other side, not coming in contact with the heavy rollers, comes out with a dull or matte finish.
The exception is when using Reynolds Wrap® Release® Non-Stick Aluminum Foil. The non-stick coating is applied during manufacturing to the dull side of the foil. Always place the non-stick (dull) side toward the food.
coming from the makers of the aluminum foil and they put their product through extensive tests to know everything about it and always get the same quality. the way it conducts heat will be the same basically which is what you are doing. since the temperature difference between the shiny side and not is also hard to measure without accurate instrumentation what difference would it be on cooking if it was something like a .0002 temperature difference because that is VERY minimal. that temperature difference on a hookah would not matter in any way because it is so small.