Growing up, canned food was opened by using a hand-operated (or automatic, if you were rich) "tincan opener". It was a pain to get the damn thing open, and when you did, you were lucky if you didn't cut yourself in the thumb on the sharp edges and fiddling with the little metallic thing with a razor-sharp cutting edge.

Nowadays, really just in the last few years, all the tincans I see have these little "soda can" opening things which require no external tools and opens the whole lid very easily.

"Classic"/traditional tincans are said to hold up a very long time if stored properly. Maybe hundreds of years, possibly?

What I wonder is if the easiness in opening comes with a price for the modern tincans, namely by cutting its "edible until" date closer to when it was manufactered? Maybe they are even deliberately designed such, so that people are unable to "stack up" on emergency food and keep having to buy new tincans as the olds' contents become rotten and inedible?

On the other hand, I remember eating slightly expired cans of various food, sealed with the classic method, and they were absolutely disgusting when opened... But maybe I was just unlucky?

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    $\begingroup$ The surface area of the locally thinned 'tear line' is extremely small as a percentage of the overall tin... It must have some effect, but I'd be surprised if it's very large, and I expect that modern linings will have improved shelf life by a much more significant margin $\endgroup$ – Jonathan R Swift May 21 '20 at 14:25

The actual can is put together the "old fashioned" way; it's just that the top is equipped with an easy-open tab.

This is supposition, but if you add a vibration specification to "proper storage", then an easy to open can should last as long as an "old fashioned". That groove is going to create a stress riser that, in an intense vibration environment may have trouble -- but if you're not bolting your tin cans to any machinery that's operating continually, then you're probably OK.

But -- "I remember eating slightly expired cans of various food, sealed with the classic method, and they were absolutely disgusting when opened."

That's because even if the can maintains its integrity over time, the food that's inside the cans are not in a state of chemical equilibrium going in, and even though storing that food with a minimum of oxygen in an environment with no living matter inside is going to extend its life, it's still going carry on with whatever chemical reactions it can -- and for the most part that's going to make it taste bad.

So even if the can lasts forever, the stuff inside is still going to degrade, at a rate depending on what's in it.

Here's more than you'd ever want to know about tin cans: http://www.fao.org/3/t0007e/t0007e.pdf


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