Why are potato chip bags puffed up?
Short answer
The bag contains packaging gas, often nitrogen, which helps protect the chips from oxidation and cushions them during transport.
How it works
Oxygen can react with the oil in potato chips and change their flavor. Replacing much of the air in the package with a lower-oxygen atmosphere and nitrogen helps slow those changes.
The space inside the inflated bag also acts as a cushion when the package is squeezed or moved. The amount of food is measured by its labeled weight, not by how full the bag looks.
Key point
The gas inside is not necessarily ordinary air. Packaging varies by product, but nitrogen and extra space help protect flavor and reduce breakage.