Boiling point of water and altitude

Discussion in 'Meat Thermometers' started by richoso1, Aug 2, 2007.

  1. richoso1

    richoso1 Smoking Guru OTBS Member SMF Premier Member

    When checking your thermometers for accuracy remember that altitude does effect the boiling point of water. The boiling point for water is 212* at sea level. For every increase of 500 ft. in altitude, the boiling point of water will decrease by 1*. This may not seem as much, but at some higher altitudes there willl be a difference of several degrees. I'm at 187 ft. above sea level, but I can't split degrees on my thermometer so my boiling point of water is 211*. Just don't think that the thermometer is off by so many degrees without considering the altitude. I know this may be overkill, but some techies will enjoy it.
  2. cajun_1

    cajun_1 Master of the Pit OTBS Member

    ok..that being do the people in the higher altitudes calibrate their thermometers ??? I,m about 4000 ft. (3733 ft.)
  3. richoso1

    richoso1 Smoking Guru OTBS Member SMF Premier Member

    At 4000 ft. above sea level you divide that by 500, and you get 8. For every 500 ft. it drops 1*. So your therm should read 204* (212* minus 8*) at the boiling point of water. If your therm reads differently, mark down the diiference. I hope this helps, let me know the results of your testing. You''ll often find this info. on boxes of cake mixes.
    * As a side note, when I first went to Twin Falls the population was 38,000 and elevation was about 3800 ft. above sea level, at that same time Idaho Falls had a population of 48,000 and an elevation of 4800 ft. above sea level. My how cities have grown.
  4. vulcan75001

    vulcan75001 Smoking Fanatic OTBS Member

  5. cajun_1

    cajun_1 Master of the Pit OTBS Member

    That's what I thought. ( Just wanting to be sure ). Have 1 therm correct, others + /- by 5*. Thanks for the info.
  6. cajun_1

    cajun_1 Master of the Pit OTBS Member

    Thanks Richard..Good website. It's now a favorite.
  7. deejaydebi

    deejaydebi Smoking Guru

    I posted that for Lisa a while back and could find it again
  8. cajun_1

    cajun_1 Master of the Pit OTBS Member

    Thanks Deb. Think I have the hang of it now.
  9. coyoterick

    coyoterick Newbie

    Beware! The calculator at that link can give false values unless you realize and understand a very important thing!

    It only asks you to enter Barometric pressure, and will then display the boiling point of water at that pressure. The problem is, if you obtain your local barometric pressure from an online service like or other web site, is that the pressure they list for your area IS ADJUSTED FOR SEA LEVEL! [font=Verdana,Helvetica,Arial]To perform a valid boiling point calculation, the calculation MUST include your elevation so the sea level adjustment can be "undone". [/font]In other words the primogrill calculator will only work if you have your own barometric pressure gauge.

    A MUCH better calculator to use is the one at
    You enter your elevation and your adjested barometric pressure and it'll display the correct boiling point of water.
  10. richoso1

    richoso1 Smoking Guru OTBS Member SMF Premier Member

    Great observation coyoterick!
  11. dutch

    dutch Smoking Guru Staff Member Administrator Group Lead OTBS Member SMF Premier Member

    The method I use is the ice water method. Fill a drinking glass 1/2 - 3/4 full with ice cubes and then fill the glass with water and let it sit for about five minutes. Stir the ice water and insert the thermo. If your thermo is calibrated it will read 32*. If not adjust the nut on the back so that needle will read 32*. This is the method that has been give in every food handlers class I've attended. The reasoning is water boils at different temp depending on altitude but it all ways freezes at 32*.
  12. bigarm's smokin

    bigarm's smokin Master of the Pit OTBS Member

    Good point Dutch, I use the ice water method too. My thermos are digital, do you know if there is any way to adjust those little buggers? All 4 of them are off, some, as much as 14 degrees. [​IMG] Terry

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