I have a love-hate relationship with my kitchen in that I LOVE eating but loathe cooking. I can’t even pretend that I select my pots and pans and appliances based on any criteria besides color and pattern — the louder the better! Not all that surprising, considering I’m the daughter of a man who despised the taste of coffee yet still bought a fancy-schmancy espresso machine in Italy cause he thought it was beautiful just as objet d’art. (Don’t worry, my father bequeathed the piece to a family friend who descaled it and brought it back into percolation.) Despite my imbalance in the culinary arts leaning heavily towards consumption rather than production, I still fairly regularly use aluminum foil. It’s a helpful tool! I’ve never known, though, if there’s a proper side to use — shiny or dull — let alone why the two sides are different to begin with. The folks at Mashed are here to help us(me) out:

The sausage-making of aluminum foil: Typically, one side of the foil is shiny while the other side remains duller. The contrast in sheen is due to the process that goes into crafting each roll of foil. According to the USDA, aluminum foil starts as a liquid alloy of metals — 98.5% aluminum, iron, and silicon. This alloy is rolled very thin and hardens as it passes through the rollers which are chilled by water. In the final rolling, two sheets of foil pass through the rollers at once. This means that only one side of the foil comes into contact with the roller itself — creating the shinier side — whereas the inside remains dull.

Milling about: This whole manufacturing process is called milling, and it is done to ensure that the foil has the right texture, shape, and properties that make it an essential kitchen assistant. Although it might be cooler if both sides of the foil were shiny, the sheets would break if only one went through the rolling process at a time, making the pairs essential.

A foil to pretty privilege: While the shiny side might be more eye-catching, that doesn’t mean it’s better. A common myth about aluminum foil is that the shinier side works more efficiently than the duller side. However, the foil is made out of the same material on both sides, so largely, whichever way you use it, it will have the same effect. This goes for traditional and heavy-duty foil.

Not all ovens are created equal: The material has a plethora of uses in the kitchen and is very effective at conducting heat and ensuring even cooking or baking. The conduction properties of aluminum make it the perfect material to ensure your food stays both warm and moist while cooking. The material is safe to use in ovens, on grills, and in air fryers. However, if you’ve been using it in the microwave, you’ve been using aluminum foil all wrong. While it may not always cause issues, it can be a hazard to do so (according to the USDA, if the foil is wrinkled, you could actually create sparks). Aluminum foil can also damage convection ovens if used incorrectly, so make sure it doesn’t fall to the bottom to keep your convection oven in tip-top shape.

Sticky situation: Special non-stick foil is the only type of foil where the sides truly matter. This variety ensures that food easily comes off after cooking or baking. For Reynolds Warp’s non-stick version, the dull side of the roll is the non-stick side, so make sure that side faces up.

[From Mashed]

So basically, which side of the aluminum foil to use is only a sticking point when it comes to the non-stick variety, bah-dum-bum! (Pauses for laughter.) Well, it’s good to finally have a definitive answer, and super helpful for kitchen idiots infrequent cooks like myself that either side is effective and safe. Despite never knowing for certain if there was a proper side, my habit has always been to have the dull side touch the food while the shiny side is the surface that faces out. But I can’t honestly say that’s due to any reason other than I’m easily attracted to/distracted by shiny things. (I refer you again to my comments above re: loud colors and patterns.) Do I have it in me to switch sides now? Could I go bi-foil?! It is the 21st century after all! And if there’s one absolute truth I learned from this article (or years ago through practical experience), it’s that the only wrong way to use aluminum foil is in the microwave.

Photo Note by CB: This is why I used a 2020 photo of Robert Pattinson for this post. In a 2020 interview with GQ he blew up a microwave by using aluminum foil in it.

Photos credit: Nano Erdozain, Gustavo Fring and Backgrid