How Much Air Is In Your Crisps & Is It Actually Necessary?

Have you ever bought a packet of your favourite crisps and been surprised at the contents, or lack of? We’ve all been there, you’re craving a pack of salt + vinegar, open the bag and wonder where your crisps are. Fed up of feeling short-changed we decided to investigate why there were so few crisps in our packets and why there was, seemingly, so much air inside. We felt misled by the packets being so large yet having so few crisps inside, so we decided to measure how much air was in a variety of crisps, to see how brands compare, and research why manufacturers felt the need to fill the bag with gas.

We wanted to explore whether crisp packets were indeed misleading us or whether we more hangry than usual. It turns out though we had a point and upon exploring why crisp manufacturers put ‘air’ in their crisp packets, their justifications might not exactly be valid. Read on to find out more.

how much air is in your crisps

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Firstly, let’s start off with a disclaimer. We tested 15 packets of crisps, snacks which are known as crisps to the majority but where some are made from potato and some are made from corn. There is the age old debate about the definition of crisps. Can crisps only be referred to crisps if they are made from potato? For the sake of this experiment we looked at a mixture of both types of snacks, mainly because we wanted to satisfy both parties, partly because we like a Nik Nak and planned on eating some during this experiment.

The crisps we tested:

  • Quavers
  • Mini Cheddars
  • Popchips
  • Kettle Chips
  • Walkers standard crisps
  • Squares
  • French Fries
  • Monster Munch
  • Nik Naks
  • Skips
  • Doritos
  • McCoys crisps
  • Wheat Crunchies
  • Hula Hoops
  • Wotsits
  • Pringles

Our (first) experiment:

We decided the best way to see how much air was in a packet of crisps was by looking at the water displacement of an unopened crisp packet and the crisp contents in a vacuum sealed bag.

We put an unopened packet of crisps in a jug of water and measured the water level on the jug. We then removed the crisp packet from the water, popped the contents in a sandwich bag and vacuum sealed the content to remove any traces of air. We put the vacuum sealed crisps in the same jug of water, ensuring the water level was the same as when we put the unopened crisp packet in the jug, and then measured the water level again. Afterwards we compared the measurements and worked out the displacement.

We had the same water level per packet of crisps to make the experiment for that packet fair. We didn’t have the same sized crisp packets, as this wasn’t really possible, but we measured the packets against each other and compared them on a percentage basis, ensuring fair results.

The results:

From most air in a packet to least, we have:

  • Popchips with 72% air. Before we opened the bag we wouldn’t have guessed these would be the worst offender but after we opened the bag, we did get a incline. It was immediately noticeable that there weren’t as many crisps in the packet as you would have expected. We also found Popchips to be the most expensive packet of crisps of the snacks we tested, retailing at £3.48 per 100g. We did compare prices per the amount of air and there wasn’t a strong enough correlation to suggest the amount of air and price were related, however Popchips did prove to be over a pound more expensive than any of the other crisps on a per 100g basis.
  • Pringles with 69.12% of air. We’ve took Pringles out of the running when making comparisons because the packaging is untraditional and conventionally incomparable.
  • McCoys crisps with 59% air.
  • Kettle Chips with 55% air.
  • Mini Cheddars with 53% air.
  • Walkers standard crisps with 53% air
  • Squares with 53%
  • French Fries with 52% air
  • Nik Naks with 50% air
  • Doritos with 47% air
  • Monster Munch with 44% of air
  • Wheat Crunchies with 39% of air
  • Skips with 38% of air
  • Quavers with 30% air. We do have to add a slight admission about our Quavers experiment. We got the numbers jotted down ok but upon double checking the numbers our Quavers had a minor leakage issue. Soggy quavers do not look appetising in case you were wondering.
  • Hula Hoops with 28% air.
  • Wotsits with 18% air. These had the least amount of air in the packaging, with a whopping 82% of actual crisps in the bag. Wotsits we salute you.

Brand Comparisons

To delve into this topic further, we decided to do a brand comparison and look at how much air was added to crisp packets by the different manufacturers. We wondered if some brands were worse offenders than others, and we also wanted to discover how much air was necessary on average for a typical packet of crisps.

Some manufacturers do dominate the crisp industry, KP and Walkers have a variety of bestselling and popular crisp brands in their groups. We featured 7 types of Walkers crisp brands and 5 KP crisp brands. We didn’t choose crisps on a brand basis, we chose crisps based on their popularity status, so this gives you an idea of their monopoly of the crisp industry.  When we compared Walkers and KP products we did draw an interesting and unexpected conclusion. On average, they added a similar amount of air into their crisp packets. Walkers added 42.37% on average and KP added 42.63% – it can’t be coincidental that the two largest crisp manufacturers add the same amount of air on average to their packets, so we reckon from our research this is an appropriate amount of air to add to the crisps.

We found that independent crisp brands, with less of a monopoly on the industry, added more than this average and perhaps an unnecessary additional amount. Jacobs added 52.63% air, Kettle Foods added 54.55% and Popchips added 71.88%.

But is it air in your crisps?

The answer is actually no. The gas you find in your crisps, while you might expect it to be air, is actually Nitrogen. Crisp manufacturers state they add nitrogen to their crisp packets to expel air, which otherwise would turn your crisps stale. Nitrogen is added to preserve the freshness of oven baked crisps and expand their best before dates. It is also added to protect the crisps – the nitrogen is meant to stop the crisps banging together and breaking in the packet while in transit.

Now being slightly cynical we decided to test both reasonings because let’s face it how many broken crisps do you often find in your packets?

Comments from the crisp manufacturers:

We were going to contact a representative from the crisp manufacturers but we found the answers to our questions about their packaging readily available on their websites.

Walkers claimed the Nitrogen was for protection of the crisp.

“Our packets of crisps are filled by weight.  You should always find that the packets weigh the grammage stated on the packet. However, there is a very good reason for the packets not being filled right to the top. Crisps are very fragile and can get crushed very easily. To try and prevent this from happening, we put air in the packs before they are sealed to act as a cushion for the product during transit. This does mean that the packets have to be a bit bigger than the contents.”


KP have made efforts to reduce their packaging by 11%.

KP claim they have reduced the amount of packaging they use when producing their crisps. The ‘introduced multi-flow technology’ which enables them to make a more ‘compact packet size’. They also state their packaging is entirely clear with reference to contents, the weight is in fact stated on the packet.


Popchips claim the Nitrogen is to keep the crisps fresh and crispy.

“Our special air-tight bags help make sure popchips stay fresh and crispy.” They do however also repeat on their website that they add no preservatives to their crisps.


So in summary the main claims for adding Nitrogen are to protect the crisps from damage and preserve the contents for longer.

Further research and a second experiment:

In regards to the best before dates, we checked out all our packets and found that the majority had less than 55 days of use from their best before date. We would perhaps expect longer use for the amount of air added, but that is arguable.

In regards to the broken crisps, we decided to conduct another experiment and throw some Popchips out of the window. Bear with us, there was a method in this madness. We bought some more unopened packets of Popchips. We opened two packets, put the contents of one in a bag filled with air and the contents of the other in a vacuum sealed bag. We counted the contents before, evened out the numbers and removed any broken crisps before to make this experiment fair.

We then threw both bags out of the window and measured how many crisps were broken after a fall from a second floor window. The results? The vacuum sealed bag had one less broken crisp compared to the air tight bag.

4/14 chips were broken in the inflated bag after falling.

3/14 chips were broken in the deflated bag after falling.

So, are crisp manufacturers misleading us?

Some are, some aren’t but it is arguable whether you can stake your claim to make them change their ways when they do list the weight of the crisps on the packaging. Having said that, USA Today reported that two people were suing Wise because their crisp packets were less than half full.  

It is certainly true that some crisp manufacturers are adding more Nitrogen that necessary and as a result you are getting less crisp content, and in the case of Popchips if this is the case why are they charging you more than most. I guess that’s a question for them. Looking at the brand claims, the result of our experiments and comparing manufacturers however, it seems 42% of nitrogen is a good industry average for packaging and any more than that, you are losing out.

How did you favourite crisps fair?

how much air is in your crisp packet

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