Does it cook faster? slower? Does it matter?.or is it just a matter of the rolling process that makes one side shiny and the other dull.any chemists or knowledgeable cooks/chefs out there? Just curious.I usually cook shiny side out.??????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 foodThe difference in appearance between dull and shiny is due to the foil manufacturing processIn the final rolling step, two layers of foil are passed through the rolling mill at the same timeThe side coming in contact with the mill\'s highly polished steel rollers becomes shinyThe other side, not coming in contact with the heavy rollers, comes out with a dull or matte finishThe exception is when using Reynolds Wrap® Release® Non-Stick Aluminum FoilThe non-stick coating is applied during manufacturing to the dull side of the foilAlways place the non-stick (dull) side toward the food.Other related question