Why Are Potato Chip Bags So Shiny Inside?

Bright colors and bold lettering might bring you down the potato chip aisle at the store, though we all know it's what's on the inside that really counts. But, we don't mean the chips themselves; what about the shiny interior of the chip bag?

Have you ever wondered why the inside of potato chip bags have such a sheen to them? Well, the answer is all about keeping the product within the bag fresh and protected from anything that could ruin its tasty qualities. That's right, the aluminum lining within your potato chip bag is quite literally your snack's knight in shining armor. It defends your chips from becoming soggy or stale.

You might wonder why not use a clear plastic to line bags? Or what about silicone? There's actually a number of reasons chip bags work the way they do and why manufacturers design bags with aluminum lining and other features. Every bit of packaging material has a purpose. 

Typically, potato chip bags are made of layers of a specific type of plastic called oriented polypropylene and aluminum. This composite of materials protect the chips from elements like moisture, oxygen, and sunlight which can all cause the food to deteriorate. The polypropylene helps to protect against moisture and the aluminum strengthens that protection.

On top of moisture protection, the aluminum layer inside potato chip bags shields chips from dust particles, some bacteria, and bad odors; plus, all this added protection helps give chips an extended shelf life. Potato chip manufacturers also protect the snack from getting crushed by pumping the bag full of nitrogen gas before sealing it. The nitrogen gas doesn't affect the flavor of the chips the way oxygen would.

But of course, when you've given into buying the jumbo bag of chips and can only get through a quarter of it in one sitting, it's hard to know how to keep potato chips fresher for longer. You could always use a chip clip or fold the bag over, but either way you've let the nitrogen out of the bag and oxygen in. The most plain potato chips out there are on an even playing field if you consider this packaging formula. The ultimate ranking of plain potato chips can thankfully rely on just the flavors.

Even just look of the aluminum does some work, and it's not only about preservation. The reflective, shiny aspect of aluminum foil naturally draws the eye. Now, what have we learned? You shouldn't blame yourself for your love of potato chips because well they're literally scientifically designed to be as enticing as possible. So, crunch away my friends. Give into the shiny bag.