A strange refractometer request

Discussion in 'General Discussions and Advice' started by Tony, 13 Sep 2011.

  1. Tony

    Tony

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    Hi Hennie. I have a strange request. Can a salt refractometer be calibrated to read sugar concentration using a known sugar solution to calibrate it. Here's why!

    Being a chef by profession we use refractometers to make ice cream by measuring the amount of sugar in the mixture which will tell us if the ice cream will freeze to hard or too soft. One can buy sugar refractometers but they are double the price of salt meters. So, I would like to buy a salt meter and calibrate it to read sugar. Can this be done, and if so, how? I know it's not marine related but I would appreciate your help where possible
     
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  3. Nemos Janitor

    Nemos Janitor

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  4. RiaanP

    RiaanP Moderator

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    I have one.

    Its to measure the sugar level in my home brew beer :thumbup:
    ( If it was to sweet, you get heartburn easily. )

    Well that was during my varsity years. Bring back very happy times. Damn heaviest brew I made was at 12% alcohol. It kicked your butt.
     
  5. Tony

    Tony Thread Starter

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    Keith one reads sugar in Brix. A standard ice cream refractometer reads from 0-32 Brix. A salt refractometer goes over that level but the ideal reading for ice cream is 28-30 Brix. Ill check out the articles and see if I can get any info off them but I need to get a known sugar solution for calibration
     
  6. Nemos Janitor

    Nemos Janitor

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    Yes Tony the different sugar refractometers are shown in the last link. What i meant was, do you know if there is a relationship between Brix and SG?
     
  7. Nemos Janitor

    Nemos Janitor

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    Last edited: 13 Sep 2011
  8. Tony

    Tony Thread Starter

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    Hi Keith. Thanks for the link. Here are reading from the web site when typing in my sugar readings. I dont think our refractometers go as high as as the SG readings shown.

    Homebrew Refractometer Calculations / Calculators

    Brix <=> Specific Gravity
    Specific GravityBrix/Plato1.
    Converting Brix during fermentation to Specific Gravity - will now calculate SG below 1.000
    Original GravityMeasured BrixCorrected Specific GravityCurrent Approx. Alcohol1. % vol
    Finding Original Gravity from Brix and Hydrometer reading
    Measured Specific GravityMeasured BrixOriginal Gravity1.
    Credit for the last formula goes to Bill Pierce
     
    Last edited: 13 Sep 2011
  9. Tony

    Tony Thread Starter

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    OK, so it doesnt show the readings but basically 28 Brix is equal to a SG of 1.2. I must go and look at my refractometer
     
  10. Nemos Janitor

    Nemos Janitor

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    Tony if your measurement range is Brix 0 - 17.3 then the standard refractometer will work because they go from 1.000 - 1.070.

    If your Brix range is 23.75 - 30 then calibrate the refractometer with a reference of 1.1.

    If the range is between 17.3 - 23.75 then calibrate with a 1.05 reference. Just remember to add 0.05 to the sg reading.

    I would try that and see how it go's
     
  11. Nemos Janitor

    Nemos Janitor

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    28 Brix = 1.120

    Sorry Tony, I edited my one post by adding a conversion table. not sure you have seen it.
     
  12. Tony

    Tony Thread Starter

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    OK, no my brain is rattled. How would I calibrate it with the 1.05 reference. I currently calibrate it to read zero with distilled water for my salt water

    I'll check it out
     
  13. Tony

    Tony Thread Starter

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    So looking at the link to the conversion table, a SG of 1.12 (low salinity SW) is equal to 28 brix and a SG of 1.130 (what will kill a fish) is equal to 30 Brix? Am I interpreting this right? If so I'm sorted and I would just have to think a little differently
     
  14. Nemos Janitor

    Nemos Janitor

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    We normally use RO water to calibrate the refractometer at a SG of 1.000 because RO water is a easily obtainable 1.000 reference solution.

    If you now have a reference solution of 1.050 and calibrate the refractometer so that the reference solution of 1.050 = 1.000 on the refractometer when taking a reading just add 0.05 to the reading.

    If your target reading is Brix 23 i would suggest calibrating with a reference solution of 1.100 = 1.000 and adding 0.1 the the reading. This will bring the target reading more into the scale compared with the end of scale reading with a 1.050 calibration.

    Hope this is making some sense to you.
     
  15. Nemos Janitor

    Nemos Janitor

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    1.012 is low salinity Tony. We are much higher up the sg scale at 1.120
     
  16. Nemos Janitor

    Nemos Janitor

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    OK tony there is an easy solution.

    Get your known Brix sugar solution (say Brix 28) and calibrate the refractometer so that the blue line is on (1.020)

    This would now be the new conversion scale.



    [FONT=Verdana,Arial,Verdana,Arial,Helvetica]1.020 = [/FONT][FONT=Verdana,Arial,Verdana,Arial,Helvetica]28.05[/FONT]
    [FONT=Verdana,Arial,Verdana,Arial,Helvetica]1.021 = [/FONT][FONT=Verdana,Arial,Verdana,Arial,Helvetica]28.26[/FONT]
    [FONT=Verdana,Arial,Verdana,Arial,Helvetica]1.022 = [/FONT][FONT=Verdana,Arial,Verdana,Arial,Helvetica]28.47[/FONT]
    [FONT=Verdana,Arial,Verdana,Arial,Helvetica]1.023 = [/FONT][FONT=Verdana,Arial,Verdana,Arial,Helvetica]28.68[/FONT]
    [FONT=Verdana,Arial,Verdana,Arial,Helvetica]1.024 = [/FONT][FONT=Verdana,Arial,Verdana,Arial,Helvetica]28.89[/FONT]
    [FONT=Verdana,Arial,Verdana,Arial,Helvetica]1.025 = [/FONT][FONT=Verdana,Arial,Verdana,Arial,Helvetica]29.10[/FONT]
    [FONT=Verdana,Arial,Verdana,Arial,Helvetica]1.026 = [/FONT][FONT=Verdana,Arial,Verdana,Arial,Helvetica]29.31[/FONT]
    [FONT=Verdana,Arial,Verdana,Arial,Helvetica]1.027 = [/FONT][FONT=Verdana,Arial,Verdana,Arial,Helvetica]29.52[/FONT]
    [FONT=Verdana,Arial,Verdana,Arial,Helvetica]1.028 = [/FONT][FONT=Verdana,Arial,Verdana,Arial,Helvetica]29.73[/FONT]
    [FONT=Verdana,Arial,Verdana,Arial,Helvetica]1.029 = [/FONT][FONT=Verdana,Arial,Verdana,Arial,Helvetica]29.94[/FONT]
    [FONT=Verdana,Arial,Verdana,Arial,Helvetica]1.030 = [/FONT][FONT=Verdana,Arial,Verdana,Arial,Helvetica]30.15[/FONT]
     
    Last edited: 13 Sep 2011
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  17. Tony

    Tony Thread Starter

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    It makes sense. Thanks for your effort in this totally non marine exercise. I'll fiddle with my refractometer and see how it goes
     
  18. Reef Maniac

    Reef Maniac MASA Contributor

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    Interesting discussion...

    Tony,

    Apologies for only responding now, but I've been attending a conference since Sunday afternoon, and have only now returned back home. Sorry that I missed the interesting discussion, but it looks like Keith has sorted the problem - Thanks, Keith :thumbup:

    Just one slight concern I have (don't know if it is significant...) - I suspect that the refractive index of sugar (or sugar water ??) could be slightly different from that of fresh or salt water, and I'm not sure if one could just use a conversion factor. I suggest that you make two sugar solutions of known concentrations, and then check to see if they give you the expected SG as per Keith's chart.

    Hennie
     
  19. Tony

    Tony Thread Starter

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    Thanks Hennie and Keith
     
  20. IMarine

    IMarine

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    excellent info,you never to old to learn
     
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