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Freezing salty water

  1. Aug 25, 2008 #1
    Iv'e freezed a bottle of water, which was feeled up to the top, with no room for air. After I took it out of the freezer I of course licked the ice, and it taseted like salt (not very pleasent)!!
    Is it salt?
    If you freeze ice in a bottle which does have some space for air this doesn't happen... I suspect it has to do with the expantion of ice as it freezes, but what's REALY happening there?

  2. jcsd
  3. Aug 25, 2008 #2


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    I have no idea what you are talking about. Water expands when it freezes. If you actually fill a bottle to the top and then freeze it, either the bottle breaks or the top is pushed off. You titled this "freezing salty water" which, grammatically, implies that the water was salty before you froze it. Did you mean "salty frozen water" which would imply that the water tasted salty after it was frozen? I can't speak for your taste buds, but certainly, freezing water will not add salt to it!
  4. Aug 25, 2008 #3
    Yoni, was the bottle filled with just plain water, or did you add salt to it before freezing?
  5. Aug 25, 2008 #4
    I didn't add salt. I did the experiment with two seemingly similar bottles, and only the full bottle tasted "not good". And the water was very regular... maybe I should try the experiment with purified water...
  6. Aug 25, 2008 #5
    The way I know is if you freez water it will expand and will have air .but i don't know about salty thing .........you should give us some explantion about your experiment and what you target or out come will be.
  7. Aug 25, 2008 #6
    If you freeze salt water then the ice you get will contain less salt per water molecule: some of the salt will be expelled from the ice. This leads to a layer of water with a higher concentration of salt that is not frozen. If you lower the temperature even more then you get a new ice layer containing more salt, but that ice layer will also have expelled some salt, so you'll have a layer of water that is even saltier.

    This process is called brine rejection, the details of this process are not understood very well see e.g. here
  8. Aug 25, 2008 #7


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    Note: even fresh water is salt water. It's just a question of how salty it is. So freezing a bottle of water, if it freezes from the bottom up, will result in a higher concentration of salt and other minerals at the top. Enough to taste? Mabye.
  9. Aug 25, 2008 #8


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    I'd guess that if the bottle is filled up to the top, the segregated brine is conveniently located for you to taste. If the ice level is below the neck, there is not only less total salt in the original sample (and drinking water does contain minerals added to improve the taste), but also the brine may be sitting around the edge at the inside of the bottle and therefore unavailable to your tongue.
  10. Aug 25, 2008 #9
    Your tongue may get small cut for the ice is too cool, the taste is your blood !
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