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OG reading

Discussion in 'Beginners Beer Brewing Forum' started by BDN, Nov 3, 2012.

 

  1. #1
    BDN

    Member

    Posted Nov 3, 2012
    I just brewed a Holiday Ale and wan't to test the OG and it was off the chart I couldn't even read it. I use a refractor . Plus how do you get FG with a refractor?
     
  2. #2
    WoodlandBrew

    Well-Known Member

    Posted Nov 3, 2012
    Was the wort watered down to the batch volume when you read it? What OG were you expecting? If it really is off the charts you could dilute a small sample of the beer with an equal volume of water and double the number that you read.

    As for reading final gravity with a refractometer. I recommend that you don't do that. Using a refractometer adds measurement uncertainty because it is dependent on the accuracy of your OG, which in this case you will not be able to read if you already pitched the yeast and would be working from an estimate.

    Although I'm biased. IMHO refractometers are fun brewing toys, but I haven't found a real good use for one when making beer.
     
  3. #3
    BDN

    Member

    Posted Nov 3, 2012
    Thanks Woodlandbrew I have not yet pitched yest but I'll try to dilute a sample to get a reading. The OG needs to be at 1.068-1.072
     
  4. #4
    menerdari

    Well-Known Member

    Posted Nov 3, 2012
    Diluting a sample will not give you an accurate reading.
    Your refract FG reading can be calculated IF you have an accurate OG reading. That said even without an OG reading your refratometer is still usefull in determining that fermentation is done by having consistant readings over several days.
     
  5. #5
    BDN

    Member

    Posted Nov 3, 2012
    Just tested a diluted sample 50/50 came up with 1.054 x2 2.108 that can't be right. :confused:
     
  6. #6
    jbeason

    Member

    Posted Nov 3, 2012
    It would be 1.108, the gravity of (pure) water is 1.000.
     
  7. #7
    duboman

    Well-Known Member

    Posted Nov 3, 2012
    If you have a hydrometer just use that, more accurate and no math involved:)
     
  8. #8
    BDN

    Member

    Posted Nov 3, 2012
    Don't have a Hydrometer will pick one up next time.
     
  9. #9
    ajf

    Senior Member  

    Posted Nov 3, 2012
    Is it a Brix refractometer? and what range of Brix does it measure?
    Refractometers come in many different flavors, and for brewing, you need one that measures from 0 Brix up to about 32 Brix.
    32 Brix is approximately 1.133. If your OG is greater than this, you will need a wider Brix range to read it.

    -a.
     
  10. #10
    BDN

    Member

    Posted Nov 3, 2012
    I just used one from my salt water reef tank.
     
  11. #11
    ajf

    Senior Member  

    Posted Nov 3, 2012
    That won't have sufficient range for brewing purposes.

    -a.
     
  12. #12
    WoodlandBrew

    Well-Known Member

    Posted Nov 4, 2012
    The problem with diluting is that you add another source of measurement error. A 10%-20% error is diluting would be easy to do if you aren't careful. Also, what is the volume of the wort? Have you diluted it to 5 gallons at this point? That could be another source of it being so high.
     
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