Why does boiling water twice make water poisonous?

I read somewhere that boiling water twice makes water poisonous and not advisable for drinking. Why is this so? Please provide a scientific explanation. Best answer will be chosen.

11 Answers

  • Anonymous
    1 decade ago
    Favorite Answer

    well, if you read it it must be true. I read somewhere that people who believe everything they read have a serious mental deficit.

    The act of boiling water can do several things:

    1. eliminates most of the dissolved gasses

    2. evaporates much pure water, leaving higher concentrations of dissolved minerals


    3. may dissolve metals or contaminants from the utensil it is heated in.

    #1 ruins the taste

    #2 & #3 could make the water unfit to drink.

    I sure wouldn't want to drink water that had beeen heated in a lead pot, for instance.

    If the pH oif the water is not neutral, concentrating the salts could cause dissolution of lots of Al from an Aluminum pot, I wouldn't want to drink that either.

    But u would have to evaporate gallons of water to concentrate enough poisons to cause harm - unless you drank that water for years.

    Distilling water (Boiling and then collecting the vapors somewhere else) eliminates dissolved minerals and non-volatiles but not organics like gasoline or alcohol. It is NOT the purist water known. Geez.

  • 4 years ago

    Boiling Water Twice

  • 1 decade ago

    Boiling distilled water in a Pyrex beaker will actually dissolve some of the glass. DI water at 100 deg. C is actually more corrosive to the Pyrex than 95 degree 5 % HCL solutions. Steam producing boilers have a tag and instruction to NOT use DI water as the source for the water to be boiled. It will eat the boiler alive. Water that has gone through a softener is acceptable and is frequently used. That has lots of Sodium from the calcium exchange. The good still of older labs used a solid block of tin for the boiler section. With the still clean and the input water low in calcium, the tin still could give you 1+ meg ohm DI water. The Pyrex still ran on tap water or softened water and produced a 1/2 meg ohm distilled water. Modern 'distilled' water production is usually done with reverse osmosis equipment and final 'polishing' filters with a recirculating system that never lets the water stand and pick up anything from the filters. The water can be as high as 22 meg ohms.

    Source(s): Experieced durability questions and solutions over the years as a glass chemist. Glass in contact with boiling water is a special animal as anyone who has to pay the price for a new boiler gage glass will tell you. Interesting to change the filters in a RO (reverse osmosis system) It's like working with swamp water. Water in piped in DI systems can smell the same if the line is not used frequently. The little bugs can live on the nutrients from the leaching of the Pyrex lines.
  • 1 decade ago

    I cannot think of any reason why it would make water poisonous UNLESS the container is composed of a substance that can be broken apart by sufficient heat to boil water and release other toxic compounds into the water. Presumably these would accumulate the more times you boil the water or the longer you boil it.

    Boiling is simply the addition of energy, usually in the form of heat, to liquid H2O. At 100°C or 373.15 K that energy is enough to excite the H2O molecules to the gas phase, which we would call steam. Applying heat causes a PHYSICAL change, not a chemical change, so, other than the effect of heat on body tissue, it will not hurt you. Boiling it twice doesn't change anything. I would be curious to see where you read this.

    As I've said, the only mechanism I can think of that would make water toxic would be that the addition of heat AND another chemical would cause a reaction to occur, either creating a new compound (H2O + MoleculeA --> Toxin) or releasing molecules into solution in the water.

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  • Nancy
    Lv 4
    4 years ago

    I asked my OBGYN if it was safe to go into a hot tub while pregnant, he said that it would be fine in small spurts and that the temp of the water was like 102 or103 at the most, and not to over do it. At 103 the water is not hot enough to turn my skin red, but any higher it would. If it turns your skin red then it may be a bad idea to bath in that hot of water while pregnant. You could talk to your Dr and get the facts from him as well, but you will not boil your baby.

  • Anonymous
    1 decade ago

    (1) Too hot for drinking

    (2) Boiling water may dissolve more substances, more poisonous substance, minerals, etc

  • Anonymous
    1 decade ago

    This is absolutely untrue. Boiling H2O will kill almost all bacteria and other nasties. Reboiling it just raises the temperature. At most, it will tast a bit off since boiling water tends to remove any free oxygen in the water. (Think soda without CO2).

  • Anonymous
    1 decade ago

    Not true. It won't help the taste, because boiling drives out the dissolved air, but the water is not rendered toxic as a result.

  • Anonymous
    1 decade ago

    You misread. Actually, boiling water twice ( and letting it cool in between ) is the way to make clear ice. ( that is a bar secret )

  • 1 decade ago

    You are ahving a wrong concept about it .

    boiling water is not poisonous instead of it it becomes's the purest water becaue it is bacteria free , germ free and is in its pure state..

    So boild water is the purest water in the world..

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