Hydrometer drifting

Discussion in 'General Brewing Discussions' started by okoncentrerad, Feb 11, 2018.

  1. okoncentrerad

    okoncentrerad Active Member

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    Is it normal for hydrometer to need "recalibrating" over time? I've noticed mine has been drifting from when I used it first, in a 20 degrees Celsius water it showed something like 1.006.... but when I'm checking it now it's close to 1.000
     
  2. jeffpn

    jeffpn Well-Known Member

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    I don’t know how you could recalibrate it. I broke one once. I tried to pull the paper out. It was stuck to the glass. I’m amazed that can get the paper exactly where it needs to be! It should read 1.000 in distilled 60° water, as you know. Try spinning it. Maybe is got an air bubble stuck to it.
     
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  3. Head First

    Head First Well-Known Member

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    It's common for them to be off a little that's why there's a place in your profile for correction. It shouldn't drift though. Possibly a temperature difference when testing or water change?
     
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  4. Head First

    Head First Well-Known Member

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    I probably have 7 or 8 around. Some have brix, some have plato and some even balling. I sort of collect them. One has a homebrew supply phone # of 6 digits. Was my dad's he bought in the 50s or 60s. A couple I picked up in goodwill for a buck or 2 and some were just given to me from people who don't use them anymore. Some are correct at 0 but off up the scale. The 1 I use regularly is spot on on both ends. If you get inconsistent readings there is probably another variable involved.
     
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  5. okoncentrerad

    okoncentrerad Active Member

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    Well with recalibrate I meant just check how much off it was :)
    I don't think there's a big difference in temperature, maybe not exactly the same but more or less room temperature.

    I usually give it a spinn I think but I don't test in distilled water as @jeffpn suggests, but that wouldn't explain a difference. But anyhow, if it shouldn't be drifting then it's either reading/handling error on my side or a change in the water. I've always tested with my tap water.
     
  6. Head First

    Head First Well-Known Member

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    There is a hydrometer temperature calculator on this site. You could play on that a bit to give you an idea of how temperature affects it.
    https://www.brewersfriend.com/hydrometer-temp
    Density of water does have a slight affect also.
     
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  7. Trialben

    Trialben Well-Known Member

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    My hydrometer is out 2 points below in 20c ish tap water it's been sitting At .008 for awhile now,
     
  8. wobdee

    wobdee Member

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    You need to know what temp your hydrometer is calibrated at. I have one that's calibrated at 60'f and another at 68'f. 8 degrees makes a difference in my readings so I make sure the wort temp is close to the calibrated temp.
     
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  9. Gledison

    Gledison Active Member

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    You should definetly check with destilled water. Depening on where you are variations of soluble salts in water are quite high.
     
  10. Nosybear

    Nosybear Well-Known Member

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    And you can't calibrate a hydrometer. All you can do is note the offset and apply it when you measure. As mentioned above, check it with distilled water at the proper calibration temperature (60° or 68° F, should be marked somewhere on the hydrometer scale). And if it's drifting, that is, you're getting different readings under calibration conditions between tests, get rid of it and get another. It shouldn't do that, the only way it could is if the paper scale inside the tube is moving and if that's happening, you need a new one.
     
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