“Packaging gas” on a label means a gas deliberately flushed into the pack before it is sealed. For chips and crisps it is almost always nitrogen (INS 941); carbon dioxide (INS 290) and argon (INS 938) are also used for some foods. The puffy bag is not filled with ordinary air: the nitrogen replaces the oxygen-rich air that would otherwise be sealed in.
Oxygen makes the fats in fried snacks go rancid, producing stale, cardboard-like flavours. Keeping it out slows that change, so chips taste fresh and stay crisp for months. The gas also cushions the contents during transport, which is why chip bags look generously filled.
Lay’s Stax Original lists “Packaging Gas (INS 941)”, and Lay’s bags of ridged and flat chips do the same. Nitrogen makes up about 78% of the air we breathe, has no smell or taste, and simply mixes back into the air when the pack is opened.
