Frozen Salty Water: What's Really Happening?

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Discussion Overview

The discussion centers around the phenomenon observed when freezing water in a completely filled bottle, particularly regarding the taste of the resulting ice and the potential presence of salt. Participants explore the implications of water expansion during freezing, the effects of salt in water, and the conditions under which the taste may change.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • One participant reports that freezing a completely filled bottle of water results in ice that tastes salty, raising questions about the underlying processes.
  • Another participant challenges the premise, stating that freezing water does not add salt and questions the clarity of the original post's title.
  • Some participants inquire whether salt was added to the water before freezing, seeking clarification on the composition of the water used.
  • A participant explains that freezing salt water leads to brine rejection, where some salt is expelled from the ice, potentially increasing the salt concentration in the remaining liquid.
  • Another participant suggests that even fresh water contains some salt, which could lead to a higher concentration at the top of the ice if frozen from the bottom up.
  • One hypothesis is that if the bottle is filled to the top, the segregated brine may be more accessible for tasting, while ice below the neck may not present the same concentration.
  • A humorous remark is made about the potential for a taste sensation being due to blood from a cut on the tongue, rather than salt.

Areas of Agreement / Disagreement

Participants express differing views on the presence of salt in the ice and the implications of freezing water in a filled bottle. No consensus is reached regarding the cause of the salty taste or the conditions affecting it.

Contextual Notes

Some assumptions about the water's initial composition and the freezing process remain unaddressed, and the discussion includes varying interpretations of the effects of freezing on water and salt concentration.

Yoni
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Hello,
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 expansion of ice as it freezes, but what's REALY happening there?

Thanks
 
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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!
 
Yoni, was the bottle filled with just plain water, or did you add salt to it before freezing?
 
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...
thanks
 
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.
 
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 http://link.aps.org/abstract/PRL/v95/e148501"
 
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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.
 
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.
 
Your tongue may get small cut for the ice is too cool, the taste is your blood !
 

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