Distilled Water Storage Issue
Date: Winter 2009-2010
I am a high school chemistry teacher who keeps jugs of
distilled water in my room for the purpose of making solutions. I
have experienced some bizarre behavior from these jugs of water and
would like to know what you make of it. Jugs of water will become
half-full after sitting for a period of only one or two months with
no leakage. The lids are still firmly sealed. Jugs of water will
develop splits (not along the seam) through which water will leak.
Jugs of water will shrink and deform as if someone has placed a
heavy load on them (which no one has). And the most mysterious
occurrence of all - as I am lecturing, all of a sudden a jug will
actually explode as if struck by a bullet. My room does not
experience temperature swings that would account for thermal shock
and no one is in my room (I keep it locked) when I am away.
I am not sure I can resolve your problem. It sounds weird. However, the
solution to the problem is to change containers. Use glass jugs instead
of "plastic". Glass has had several centuries of testing for the storage of
distilled water. That is a pretty good track record. If you continue to have
a gas pressure buildup, you probably would have to look at some sort of
microbial growth. But I suspect you just want to problem to go away. Another
suggestion is to clean and rinse the storage containers on a more frequent
One issue I always had storing distilled water is that it absorbed carbon
dioxide from the air and becomes very acidic. pH of 4 or lower by some
test observations. Since I would use this water for activites that often
involved living materials, I used a buffer to neutralize the acidic quality
of the water, but that may defeat your purposes. My idea is
that you may have some chemicals sublimating nearby that is reacting with the
acidic quality of the water or the pH is having a detrimental effect on the
plastic. Aged plastics often do not behave as predicted.
Using glass and making the container air tight may solve your issues.
Your experience is truly unique.
What are your jugs made of?
How is the lid sealed on (Screw top cap, cork, or something else?)
What is the volume of your jug, a liter?
Is it possible someone took some water out of the jugs without you knowing
Evaporation is the only other possibility I know of, but half the volume
over a month is too much to account for evaporation.
Have you tried exorcism!! Seriously, what is the material of construction
of the jugs? It sounds like the water is extracting a water soluble
component from the plastic jug. This is weakening the walls and also making
them brittle, hence subject to "catastrophic" failure. The pressure
collapse suggest a process similar to the crushing of a paint can by the
atmosphere when the air in the can is expelled by boiling water, and the
can's spout is sealed by tightly screwing it on.
I would alter the jugs and inform the vendor. Ask for a refund and
replacement by another material. Show the vendor the results of one of your
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Update: June 2012