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The Science Behind the OXO POP Container Airtight Seal

We dive into how the iconic push-button storage containers actually seal to keep food fresher, longer.

4 min read

OXO POP Containers are our much-loved food storage solution that have found their way to millions of pantries, cupboards, restaurants—even classrooms and under bathroom sinks. We created our POP Containers to help keep pantry staples like flour, sugar, coffee beans and snacks fresher longer and to help keep clutter at bay. You might wonder how exactly the containers do that— the answer is in their airtight seal.

opening POP container

How a Refrigerator Door Inspired POP Containers

When investigating the science behind sealing, we immediately thought of a refrigerator. Walk by a refrigerator and you don’t feel cool air escaping. The door opens easily when you grab the handle; close the door and the refrigerator is sealed.

POP is no different. We designed an internal, patented web mechanism (go Behind the Design of the POP Containers to learn more) in the lid that causes the silicone seal to act like the seal around your refrigerator door. When you press the button, the web expands, pushing the seal, or gasket,out against the container walls, creating a barrier that prevents air from escaping.

smoke bomb in POP Container
Smoke does not escape from the container once it is sealed. We're demonstrating this with a colored smoke bomb in a lab with a professional engineer. Do not attempt at home.

When you press the POP button, the web in the lid will expand or contract, depending on whether you’re closing or opening the container. When the web contracts, the seal is temporarily “broken” and air can start to escape.

How to Get the Proper Seal

The silicone gasket has a thin center “fin”. When engaged, the gasket expands, and the fin pushes against POP Container bodies to create an airtight seal.

testing POP seal
The silicone "fin" seals against container walls when the button is pressed.

That silicone piece is flexible when it’s moved (like from wiggling the lid to open the container) it can temporarily break contact between the fin and the container walls. This allows air to come in and the lid to come off. That’s why we recommend grabbing the containers from the base instead of their lid and always using the button to release the seal. 

Measuring Seal Consistency

We design our POP Containers to seal the same way, every time you use them.

calibrating POP web

OXO engineers carefully calibrate the internal web mechanism and the container – ensuring every web – and fin – expands  flush against side of the container. Think back to the refrigerator analogy: we’re checking that the refrigerator door is the right size to close snugly into the refrigerator but also the right size to open easily.

In addition to conducting weight tests (putting different amounts of weight in POP Containers and turning them upside down to test the strength of the seal), we also test the POP Containers by filling them with pressurized air and measuring the amount of air that escapes. With a proper seal, no air escapes.

weight test for POP
We conduct weight tests to test the strength of the lids.

Now that you know how POP Containers work, here’s a handy size guide that pairs pantry staples with their perfect POP partner.


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