This is an outdoors & chemistry question.

I have an old and functional water bladder, shown below. On it, there are markings that coffee, beer, wine, hot drinks etc. must NOT be stored inside, only water.

While I realize that wine is acidic, damaging the bladder and becoming poisonous, beer seems to me quite close to water. Furthermore, I indend to test it with weisbeer, which does not contain such a large amount of gases as to explode.

Would be safe for me to store non-fizzy beer for up to a day every day in a "do-not-store-beer-inside" water bottle and then safely drink it?

enter image description here

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    $\begingroup$ You probably will need to specify the type of plastic used (usually it's embossed on the body) $\endgroup$ Commented Jul 23, 2013 at 18:29
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    $\begingroup$ In order to be able to give useful and reliable advice, we really need to know the type of polymer that the container is made from. If it's manufactured in the US, then there should be a triangular recycling symbol molded into the plastic. The number in that symbol corresponds to the plastic used in the container. As an aside, if you're concerned about acidity, beer is also typically more acidic than water and contains a variety of phenols and carboxylic acids. It's entirely possible that those compounds could accelerate the degradation of the plastic and leech unhealthy substances. $\endgroup$
    – Greg E.
    Commented Jul 24, 2013 at 3:38
  • $\begingroup$ Unfortunately, no indication of the used plastic is indicated on the case, and I have thrown away the packaging. Please give me general/worst case advice. Should I discover the used plastic, I shall post a new, more concrete question. $\endgroup$
    – Vorac
    Commented Jul 24, 2013 at 7:19

2 Answers 2


I doubt that this is a chemistry problem. Food safe plastics which can hold wine and coffee are so abundant and cheep, there is no reason that they went to the trouble of finding one which is not suitable for these, but suitable for water, and made the bladder out of it.

All beverages beside water are a good growing medium for one microorganism or another. And the bladder is hard to get clean, the sucking straw even more so. So, it looks to me that they are warning you to not put in anything beside water because you'd risk starting your own bacterial or fungal colony. Beer is as bad as other drinks - don't store it there.


From the description, the plastic will capture volatile compounds and you will never eliminate the smell of beer and the alcohol could disolve the plastic a bit and give the beer a plastic smell/taste.

Not a good idea.

  • $\begingroup$ Proposed experiment: I fill the thing with beer and keep it 48 hours. Then taste the beer and if it has changed taste, then it is probably poisonous. If it has not changed taste noticeably, it is not poisonous for sure. Correct? $\endgroup$
    – Vorac
    Commented Jul 24, 2013 at 7:21
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    $\begingroup$ @Vorac, not correct. You're operating under false assumptions: (a) the chemicals will be detectable by taste, when in fact they could be tasteless below some concentration; (b) if noticeable degradation doesn't occur within 48 hours it won't occur over longer time scales, which is inaccurate. If it's a polymer that degrades by acid-catalyzed hydrolysis, that can be quite a slow process. It strikes me as improbable that anything significantly toxic would leech out over short time scales, but, given that the product specifically warns against such use, why risk it? $\endgroup$
    – Greg E.
    Commented Jul 24, 2013 at 9:19

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