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The reason tinfoil has two distinct sides—one shiny, one matte—was not intended for the benefit of professional chefs or casual bakers. It’s merely an incidental byproduct of how it’s produced.
To make tinfoil (or more precisely, aluminum foil), a large sheet of aluminum is passed through heated steel rollers until it’s only 5 millimeters thick. Then, it goes through cold rollers for further thinning. As explained by CulinaryLore.com , the aluminum is already too delicate at this point, so manufacturers run two sheets together. The surfaces where the top sheet and bottom sheet make contact with the rollers become shiny. The areas where the sheets only touch each other remain dull.
Because the shiny side appears more reflective, many assume it should be on top when cooking or baking. This is logical for those using a DIY solar oven (or attempting to fry an egg on a hot day outdoors): The shiny side reflects more sunlight, transferring more heat to your food. However, most conventional ovens cook food using convection, which circulates heat from hotter areas (like coils) to cooler ones (your food). This means convection ovens are unconcerned with the reflectivity of the items inside.
However, the difference between the shiny and dull sides matters with certain types of aluminum foil. For instance, the dull side of Reynolds Non-Stick Aluminum Foil is coated with a substance that prevents food from sticking, so it’s best to place your food on that side. As TODAY highlights, the dull side of this product is labeled with the term non-stick to remind you.
Aluminum foil isn’t limited to just ovens. From sharpening scissors to cleaning grills, here are 15 alternative uses for your roll.
