eli5: Why are soup/food cans so much more robust than beverage cans, even though both cans are made to withstand the pressure of being stacked vertically for shipping and storage?

Question

Crushing a soda can is easy, crushing a soup can is way harder. The soup cans are also often corrugated. What explains the difference?

In: 3794

Answer 1

Beverage cans usually contain a liquid with dissolved carbon dioxide that creates a higher internal pressure than the outside. This makes them a lot harder to crush when unopened compared to when you open them.

Food cans do not in general have positive pressure in them, that is quite clear when you open them and nothing leaks out. There can be positive pressure in some food cans like Surströmming, it is just not common.

So the food can need to be able to substance the forces on it without the help of internal pressure and they need to be made a lot more sturdy.

If you look at a lid of a food can it be built so it can deform and even out the pressure without another part deforming. There is ofen heating stage in the manufacturing to kill bacteria in it and the content will then expand and later shrinkigg. You can also fill it with something hot the volume will decrease a bit when it cools. So food cans often get a lower pressure inside than outside during manufacturing. Corrugation is a way to get the right part to deform and to make is stronger in general.

Compare how hard they are to deform and the change in required force with an unopened and opened can. There is a lot more change for drink vs food cans because the former use the higher internal pressure to achieve the required strength.