AUG 16, 2017 5:47 AM PDT

Why Potato Chip Bags are Always Full of Air


It's snack time and you eagerly rip into a bag of potato chips only to find the bag is only half filled with actual chips. The other half seems to be filled with seemingly empty air. Is this the biggest commercial fraud or is there a reason behind all the air-filled potato chip bags?

It turns out that Lay's and other manufacturers aren't trying to deceive you, at least not with what you perceive as empty air. Potato chip bags are purposely inflated, but not with ordinary air. Rather, the bag is filled with nitrogen, which acts as a tasteless, non-toxic preservative to keep chips crunchy. That's why after a bag of chips has been open - nitrogen leaked out, and air seeped it - the chips get stale and even rancid.

The puffed up potato chip bags also serve another physical purpose. Termed "slack fill," the bag's air content serves as a cushion for the chips, without which your snack would be reduced to nibbly crumbs.

So next time you lament a chip bag that's seemingly half empty, just imagine what your snack would look and taste like without the nitrogen fill!
About the Author
Doctorate (PhD)
I am a human geneticist, passionate about telling stories to make science more engaging and approachable. Find more of my writing at the Hopkins BioMedical Odyssey blog and at
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