Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Is reboiling water bad ?

  1. Dec 13, 2015 #1
    What happens when water is reboiled? what molecular or structural changes takes place? How can that be bad ?
    Last edited by a moderator: Dec 13, 2015
  2. jcsd
  3. Dec 13, 2015 #2


    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper

    Water is water. In a power plant, it is reboiled a zillion times (of course, this is pure water which is treated to remove minerals and dissolved gasses.)

    I think the point this article is trying to make is that reboiling water in tea kettles and stuff concentrates any dissolved minerals in the remaining water which doesn't turn to steam the first time around.
    Last edited by a moderator: Dec 13, 2015
  4. Dec 13, 2015 #3
    Liquid water is H20, Ice and water vapour are other forms of H20.
    Liquid water is a very good solvent, and can easily get mixed (contaminated) with salts and other stuff. This can make it unfit for drinking.
    Boiling water turns the H20 in to steam, water vapour, contaminents are mostly left behind.
    The steam is more or less pure H20, which you can then condense, and then is drinkable water.
    That's how desalination plants work.
    Last edited: Dec 13, 2015
  5. Dec 22, 2015 #4
    If you have perfectly pure distilled deionized water, nothing will happen if you reboil it. However, ordinary water contains dissolved gases and minerals.The chemistry of the water changes when you boil it, because this drives off the volatile compounds and dissolved gases. There are many cases where this is desirable. However, if you boil the water too long or reboil it, you risk concentrating certain undesirable chemicals that may be in your water. Examples of chemicals that become more concentrated include nitrates, arsenic and fluoride.
  6. Dec 22, 2015 #5


    User Avatar

    Staff: Mentor

    While technically it is correct, it doesn't matter much as long as the volume of the water doesn't change substantially because of evaporation. Typical boiling is not long enough to seriously reduce volume of water.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook