It turns out this the real reason why chip packets are always half empty

Opening a bag of chips to find it is half empty is a common cause of dismay amongst chip-lovers globally, but apparently there is a reason for that annoying bit of extra space in the bag, reports NY Post.

The air in the bag keeps the chips from going stale too quickly while also protecting the fragile potato snacks from being damaged, according to the UK’s Snack, Nut and Crisp Manufacturers Association.

A study by CDA Appliances in 2017 proved that the average bag of crisps is actually 72 per cent empty.

What’s more, that empty space in your bag of chips isn’t just air — it’s Nitrogen gas. This is meant to prevent the chips from breaking in the bag as well as expel air, which makes the chips stale.

There’s even a name for that disappointing empty space — “functional slack-fill.”

“Slack fill occurs [most often] in snacks, nuts, candy. The weight is always accurate,” said Robert Niemman, a lawyer specialising in food-related lawsuits, in an interview with Vox.

“If it says there’s two pounds in there, there’s two pounds, probably a little bit more. But if the container is designed to hold four pounds and there’s only two pounds in there, obviously it’s only 50 per cent full.”

Due to the fragile nature of potato chips, the extra air cushioning makes sense to stop them from becoming a bag of crumbs on their way to shops and dairies.

“In addition to preventing staleness, the inserted gas also provides the added benefit of creating a cushioning effect to protect the fragile contents of a packet from damage,” a Snack, Nut and Crisp Manufacturers Association spokesperson responded to the study, according to Daily Mail.

“The packaging expands or contracts depending on the ambient temperature, whereby the gas present in the pack will fill a larger volume when it’s hotter, and a smaller volume when it’s cooler.”

Photo / 123RF

The 2017 study’s authors affirmed that the extra padding in the bag did seem to increase the chips’ life expectancy.

The everyday bag of chips has a “best before” date that expires 55 days after production, but research suggests that because of the space within the chips bag, one particular crisps brand — Popchips — can last up to 290 days before going stale.

What’s more, two chip-eaters sued Wise Foods in 2017 on the basis that their mostly air-filled bags tricked them into overpaying.

This article was first published by the NZ Herald and is republished here with permission.