When you open a bag of Lay’s, the air rushes out, leaving a few underwhelming crumbs at the bottom of a huge packet.
The extra space in the package is there for a reason. It is an intentional choice by snack makers who want to protect their delicate products from the damage of rough handling during the shipping process. When products are stacked atop one another, crammed into tight spaces, or simply jostled around in the back of a delivery truck, slack fill serves as an air cushion that prevents potato chips from becoming potato crumbs. The technical term for it is “slack fill“.
That’s not just any ordinary air. It’s nitrogen. Oxygen can cause the potatoes to spoil and the oil to go rancid, and the humidity found in ambient air makes the chips go soggy. Instead, packages are filled with nitrogen gas to help the snacks stay fresh. Nitrogen flushing isn’t harmful in any way, since about 78 percent of the air we breathe is composed of nitrogen already. However, that doesn’t excuse the sheer proportion of space that gas occupies in a bag that’s supposed to be filled with food.
Although the federal Fair Packaging and Labeling Act passed in 1966 required manufacturers to clearly indicate the net weight of their product’s contents to prevent customers from being duped by huge-seeming containers on the shelves (new and improved potato chips, now with 50 percent more air!), the regulations are rarely enforced. Humans are terrible at accurately perceiving size, and even the most discerning shoppers will automatically assume that larger packaging means more product if they don’t look too closely at the label. So while some extra space in a bag can help keep potato chips fresh and intact, any more than necessary might be the company trying to pull a fast one over us.