This question already has an answer here:

I’m posting my question because I read this original post. The post was from 2016, so I’m reposting in hopes that someone can answer. Here’s the original post: (Also, do not flag as duplicate. If you read my experience below, the answers from the previous post do not explain why this is happening.)

I'm sitting in a room next to some totally unopened cans of carbonated soft drinks (if it matters — the two affected cans are Coke Zero and Diet Coke). These cans were unboxed approximately two days ago and were full, but now are seemingly mostly empty!

There is no puncture in either can, and compressing them results in the dent being counteracted by pressure inside the can. Shaking and weighing the can (by hand; I don't have a scale anywhere near) reveals that a good majority (75%) of the can is now effectively empty.

The cans spent the whole time stored inside a normal room with a temperature of ±22ºC and automatic fluorescent lighting which is on for 16 hours a day.

Finally, there is no condensed drink on the outside wall of the can, and the cans themselves are externally room temperature, so I'm really puzzled about what process could do this.

I'm hesitant to open the cans because I'm not sure what the result of that could be, however if it's deemed here that there's little or no risk, I'll do that and update the question.

What possible reason could there be for these cans becoming empty?

Now here is my post/question:

I know exactly what you are talking about! Only my soda cans were not expired! I have a soda machine that I purchased about 10 years back. I load the machine myself with different sodas...coke, Diet Coke, sprite, dr.pepper etc....so I know that the cans are full when I put them in there.

Over the past 10 years I have found around 10-15 cans that are totally empty. Sometimes there might be a small amount of soda in them, but not much. There are no puncture holes, no sticky residue on the can, nor any residue inside the machine. Every time I found one, I thought I was going to have to clean up a mess....but nope, no mess..nothing. There is still pressure inside the can...not as much as a regular can, but there is still pressure. I’ve opened all of them. No bad reactions! Haha!

I’ve looked at the seal at the top of the can. I’ve even put one under water to look for leaking bubbles. Nothing... I’ve been perplexed for years and have asked everyone I know, and I have yet to find a viable explanation. If anyone can fill me in, I would love to know the answer!


marked as duplicate by Kyle Kanos, Buzz, John Rennie, Jon Custer, ZeroTheHero Jan 2 at 22:39

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

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    $\begingroup$ Possible duplicate of Why did the liquid seemingly disappear from some unopened aluminum cans? $\endgroup$ – Kyle Kanos Jan 1 at 23:42
  • $\begingroup$ Yes, that was the original post that was unanswered. $\endgroup$ – Amber Jan 1 at 23:49
  • $\begingroup$ huh? There are two answers posted there... $\endgroup$ – Kyle Kanos Jan 1 at 23:51
  • $\begingroup$ Both answers do not explain in my experience. $\endgroup$ – Amber Jan 2 at 0:11
  • 1
    $\begingroup$ @AaronStevens Amber didn't ask the other question, someone else did. $\endgroup$ – Kyle Kanos Jan 2 at 3:05

Found this

Throughout the process, the aluminum behaves begrudgingly. It tries to jam the machines. Once filled, it wants to interact with the product inside and change its taste. But mostly, cans yearn to corrode (thereby leaking onto other cans, and causing more corrosion). Rust, it turns out, is a can’s number one enemy—and a can’s only defense is an invisible epoxy shield, just microns thick. (Without that shield, a can of Coke would corrode in three days.) At Can School, I got a hint of what goes into that coating.

Italics mine.

As the other solutions are metaphysical (soda pixies) I make a guess:

Corrosion , if the epoxy shield is damaged, could happen with small invisible holes which might allow the molecules of the liquid to evaporate.

For such small holes it is not enough to put under water looking for bubbles. You should leave them in water and see if after some days they are filled.


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