Why There Is So Much Air in Crisp Packets?

Crisps are a staple snack enjoyed by millions, but opening a bag and finding it only half full can be disappointing. It might seem like a way for brands to cut down on the number of crisps they put in each packet and give the illusion that you get more for your money, but there’s a sound reasoning behind all that ‘air’.

Crisp Packaging: The Science behind the Air

At first glance, the air in crisp packets may seem to be taking up valuable snack space. However, it’s not really air but nitrogen.

Nitrogen is used to modify the atmosphere of the crisp packet. One of the chemical characteristics of nitrogen is its highly stable triple bond, which minimises any reaction with the ingredients within the crisp packet and keeps crisps fresh, tasty and crunchy.

This is important, as crisps contain moisture, meaning they will quickly go stale when exposed to the oxygen. Nobody likes a soggy crisp, so manufacturers reduce the amount of oxygen inside by filling the packets with nitrogen, which prolongs the crisps’ shelf life.

The Role of Moisture Measurement in Ensuring Freshness

Moisture is a critical factor in determining the shelf life and quality of crisps. Too little moisture and crisps will be hard, while too much can cause crisps to lose their crunch. Therefore, ensuring crisps remain fresh and tasty requires precise control over the moisture content during production.

Manufacturers achieve this by using Near Infrared (NIR) moisture gauges. Advanced food processing equipment such as the NDC Moisture Analyser allows producers to maintain optimal freshness and taste by measuring moisture levels in real-time.

Because NIR gauges are non-contact, they can be used to measure moisture without physically touching or destroying the product.

They work by emitting a NIR light at specific wavelengths known to interact with water (moisture) molecules. When the light reaches the crisps, the crisps absorb some of it and reflect the rest.

The light absorbed by the water molecules in the crisps depends on the moisture concentration, with high-moisture crisps absorbing more light than those with less water.

Then, a detector measures the intensity of the reflected light to accurately, quickly and continuously calculate the moisture content.

From here, manufacturers can adjust cooking times, temperatures or the drying process to ensure optimised moisture levels, consistent quality and the right balance of crunch and flavour.

The “wasted space” in crisp packets may seem excessive at first glance, but now you can see it’s not just a clever marketing trick — it is a precise solution to maintain high-quality standards and keep crisps fresh and delicious throughout their shelf life.