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
Soda cans are pressurized, and a lot of their strength comes from that fact. Much like an inflated balloon can hold its shape, and a deflated one can’t. If one takes an intact can, a person can readily stand on it without issue. Open the can and release the pressure, and the can will crumple under the same weight.
Soup cans usually have foods where pressurizing doesn’t make sense, either because the can needs a wide opening or because the food shouldn’t be fizzy. So therefore the can itself needs to take the weight without depending on internal pressure to keep it rigid.
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.
Oh man, do I have the video for you!
[*The Ingenious Design of the Aluminum Beverage Can*](https://youtu.be/hUhisi2FBuw?t=423)
In this video Bill Hammack the Engineer Guy explains *all* the facets of what makes the aluminium beverage can a fantastic invention. The timestamp is specifically where he talks about why the cans are pressurised and how that makes them strong!
EDIT: name spelling
Canning is a process that involves pressure and heat, to achieve high temperatures in sterilization of the product inside occurs.
Doesn’t matter if you are canning at home or buying canned food.
Of course, many items require a pressure canner. Not just a water bath.
Unlike soda cans, which have an increased internal pressure, canned goods actually have a partial vacuum, as oxygen is forced out during this process. Thus food storage cans (metal or glass), have to be able to survive this process.
The strength of soup cans comes from being thicker ridged steel. Beverage cans are extremely thin aluminium as there’s enough pressure on the inside to keep them sturdy.
Basically, try crushing a sealed beverage can. That’s the “real” strength manufacturers worry about.
This is about a 12 minute watch, but if you are curious about the amazing engineering behind the soda can it is worth a watch. It explains why you can crush a soda can so easily, but also why they are so incredibly strong when full.
A lot of times cans with food in them are pasteurized in the can, so they need to be able to withstand the heat and subsequent pressure.
Going to guess that thin aluminum drink cans would not withstand the heat and subsequent vacuum that cans for food are subject to. Outward pressure strengthens the soda can, if you open a tin of food and it’s not pulling a vacuum, don’t eat it!!!
The can is built for the pasteurization process and product life span not so much the stacking.
Soup cans are typically retort which require high pressure and high temperature.
Soda cans are usually just hot fill. Sometimes, there is some level of pasteurization but it’s not the same as retort.
Beer is usually straight filled as the alcohol is the preservative.
Because soup/food cans have to be sterilized, often under pressure to achieve a high temperature (known as retort). The cans will therefore need to be thicker and more robust in order to withstand the extreme temperatures and pressure.
Soda cans on the other can don’t need to be retort grade.
Latest Answers