Is Corrosion to Blame for Leaked Pepsi in Unopened Can?

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Discussion Overview

The discussion revolves around the phenomenon of a half-empty unopened can of Pepsi Max, exploring potential causes for the leakage, including corrosion, diffusion, evaporation, and manufacturing defects. Participants also consider the implications of consuming the remaining liquid and the role of can materials in this context.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • One participant suggests that slow diffusion could explain the leakage, while also expressing concern about the possibility of corrosion.
  • Another participant agrees with the diffusion theory but notes that corrosion cannot be completely ruled out, referencing the ability of coke to clean rust.
  • A different perspective proposes that the leakage is likely due to a manufacturing defect, such as improper sealing or lining application, particularly highlighting the difference between materials used by Pepsi and Coca-Cola.
  • One participant hypothesizes that evaporation, coupled with heat cycles, could have concentrated the syrup, replacing the lost liquid with gas escaping through the tab.
  • Another participant humorously speculates about atomic alignment causing the liquid to fall through the bottom of the can.
  • Concerns about health implications from aluminum exposure are raised, with one participant referencing a common belief linking aluminum cans to Alzheimer's disease, although this is met with skepticism.
  • Several participants assert that modern metal soda containers are lined with plastic, which would mitigate corrosion risks, but acknowledge that a defect in the liner could still lead to corrosion over time.

Areas of Agreement / Disagreement

Participants express a range of theories regarding the cause of the leakage, with no consensus reached. Some agree on the possibility of manufacturing defects or evaporation, while others emphasize the role of corrosion and material properties. The discussion remains unresolved regarding the exact cause and implications of the leakage.

Contextual Notes

Participants note the potential for manufacturing defects and the impact of time on the integrity of the can and its contents. There is also uncertainty regarding the health effects of consuming aluminum ions and the specific conditions that may lead to corrosion.

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About 5 years ago I bought a can of Pepsi Max. It sat at the back of a cupboard since. Whilst tidying out the cupboard, I found the can. It was however half empty. The weird part is that the can was never opened. About 150ml of Pepsi had to have leaked out, but visible on the shelf was a light brown stain.

There are a couple of questions here:
1) How did the Pepsi get out? I'm assuming slow diffusion. Corrosion is troubling to consider.
2) Apart from it probably being flat, would it be unhealthy to drink the remaining Pepsi? Would you expect a high concentration of corroded aluminium ions in the drink?
3) What would drinking aluminium ions do to you?
4) Would you expect this to be unique to the can (a material defect), the product range (Pepsi Max) or acidic/low pH carbonated drinks in general?
 
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That is very interesting and strange. I've never heard anything like that!

In an attempt to answer your questions:
1) I would also assume slow diffusion, but corrosion can't be ruled out entirely...do you know that coke can clean away rust among other things?
2) I might expect a higher concentration of aluminum ion levels...it only makes sense since its been in there for 5 years. Although I'm not sure it would be harmful to you...but then agan I'm not a medical professional so I wouldn't advise you in actually ingesting it.
3) I have no bloody clue what they might do to you.
4) I would think it would be either a product range thing or a material defect in the can.
 
It would have to be a failure of the can. Either a manufacturing defect caused incomplete sealing between the can base and sides, or (more likely, in my opinion) the lining within the can was not properly applied. Pepsi Britvic use steel cans (Coca Cola use aluminium) so if the steel was exposed then corrosion of the can would have been not only possible, but also pretty likely.

Why don't you dissect the can, clean it out, and have a look?
 
I suspect this is a result of simple evaporation. Coupled with heat cycles. As the Can heats it would force gas out through the tab. I'm willing to bet the concentration of the syrup would be higher and replacing that 150 ml with water would bring it close to the original formula.

Could Be wrong though Who knows.
 
Oooo but how to account for the brown stain?

That's the dilemma I face every morning.


(Sorry, I couldn't help myself.)
 
Maybe the atoms in the pepsi aligned perfectly with the atoms in the bottom of the can, so that the liquid fell through the bottom? :biggrin:
 
According to my mom, drinking from aluminum cans gives you alzheimer's. Apparently that's why I have such a bad memory. She explained why, but I forget the details.
 
you can rule out corrosion AND alzheimers. All of the metal soda containers are lined with a thin layer of plastic. Don't believe me? next time you open a can, look at the tab closely, and you will probably be able to see some plastic frays around the edge of the lid. If they didn't line the interior, I think it would be exceptionally dangerous to drink and bloody disgusting to boot.
 
SelmerSaxMan said:
you can rule out corrosion AND alzheimers. All of the metal soda containers are lined with a thin layer of plastic. Don't believe me? next time you open a can, look at the tab closely, and you will probably be able to see some plastic frays around the edge of the lid. If they didn't line the interior, I think it would be exceptionally dangerous to drink and bloody disgusting to boot.

But if the liner contained a flaw caused by a manufacturing defect, corrosion would be probable, especially over such time periods.
 

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