Refractometer Wort Correction Factor Results

Discussion in 'Brew Sessions' started by LarryBrewer, Apr 17, 2013.

  1. LarryBrewer

    LarryBrewer Active Member

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    We just posted a Refractometer Wort Correction Factor spreadsheet:
    http://www.brewersfriend.com/how-to-det ... on-factor/

    This thread is here for brewers to post the spreadsheet filled out with their observations so we can see if there are any trends with particular models. Should be interesting.
     
  2. ajf

    ajf New Member

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    Nice spreadsheet.
    One small fault which I found after downloading it some time ago. It may be fixed by now.
    The hydrometer units (SG or Plato) incorrectly referenced the price cell. I changed the cell reference from D7 to D9 in column G to correct that.
    A couple of documentation errors.
    • Item 4 in the instructions reads "If you don’t have unfermented wort on hand, create a wort solution that is roughly 20 °P / 1.083." What exactly does this mean?
      Item 4.3 states "Measure the solution with the hydrometer", but fails to mention applying a temperature correction.
    You recommend taking 5 samples of the same wort and averaging the results. While this will not hurt, I find multiple samples of the same wort always give identical readings. It may be worth mentioning that multiple samples are usually only necessary if you have a defective refractometer.
    You say that the WCF is specific to the instrument. This would be true if different instruments introduced inaccuracies, but it is also dependent on the grain bill. If I make a beer with 95% M.O, and 5% Crystal 60, I get a WCF of 1.020 to 1.024. If I make a beer with 90% MO, 5% crystal 60, and 5% Torrified wheat, I get a WCF of 0.985 to 0.987.
    To get around this problem, I maintain a different copy of the spreadsheet for different recipes, and apply the WCF that is specific to that recipe.

    -a.
     
  3. wksmith

    wksmith New Member

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    I am curious to know if this forum is actually active? is the sight being monitored? the previous post points out a few flaws in the spreadsheet. However, when I download it (Oct 2015) I see the version date on the spreadsheet precedes the post date identifying problems. Can only conclude that the maintenance of the sheet is not or is there an updated version elsewhere?

    Or . .. was this just a good idea that didn't get traction?
    W.
     
  4. swissRico

    swissRico New Member

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    the answer is (B) - "a good idea that didn't get traction"

    To whom it may concern,

    The error in the spreadsheet is still there.

    With regards to the actual process, I did go through it last night and started with a solution of around 17 Brix which I measured twice, diluted, measured twice, diluted and so on. This will give you an idea of the refractometer is linear, or if you have any problems.

    (This whole process also presumes that your hydrometer is a better instrument than your refractometer)
     
  5. rolandblais

    rolandblais Member

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    Reviving a dead thread :) - Yep, the cell issue is still present in the current iteration of the spreadsheet, but changing the formula in G12 from D7 to D9, and leaving it as D7 in G13 didn't seem to make a difference:

    upload_2018-10-25_15-44-57.png

    But I'm definitely going to be using this sheet as I'm curious about my refractometer compared to my hydrometer.
     
  6. Trialben

    Trialben Well-Known Member

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    I'm sure @Nosybear has dug into this topic.
     
  7. jcmurray75

    jcmurray75 New Member

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    The error in the formula should only make a difference if you're using Plato measurements rather than SG measurements - i.e. if you set the cell to 'plato' you should see a difference (with the corrected formula)

    My question is whether I should be adjusting the SG values for temperature - for example, if my hydrometer is calibrated to 60 degrees, my sample was 68 degrees, and measurement was 1.042 SG, should I use 1.042 SG -OR- adjust it for the temp difference between the hydrometer's calibration temp and the sample temp?
     

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