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Old 04-12-2009, 06:14 PM   #1
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Default Refractometer FG

I just kegged a wheat today and measured the FG with my refractometer and hydrometer. With the refractometer I get 5 brix, after accounting for the OG of 1.048 that reads as about 1.003. Meanwhile, the hydrometer reads at 1.011. Both are calibrated and temperature adjusted. Also, I am always within 2 points when comparing the two prior to fermentation.

Is this because I am measuring a wheat which typically have more particles in them than most other beers? This is the first time I have used my refractometer for FG calculations.


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Old 04-12-2009, 08:13 PM   #2
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Refractometers can only provide a very rough approximation when alcohol is present. Trust hydrometer readings for FG.


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Old 04-12-2009, 08:32 PM   #3
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I figured the hydrometer is more accurate, but I have read that most people are within a couple points when comparing the two devices. Just trying to figure out what is going on.
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Old 04-12-2009, 08:38 PM   #4
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Check out this tutorial and spreadsheet. Could help

MoreBeer!™: Using a refractometer in brewing | MoreBeer
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Old 04-12-2009, 08:42 PM   #5
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Do you use beersmith? There's an adjustment tool in there.
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Old 04-12-2009, 08:46 PM   #6
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I used Beersmith's adjustment tool, Morebeers and some other site I found. They all had the same results. Both the refractometer and hydrometer have been recently calibrated in distilled water. Something is causing such a large discrepancy, my guess is that I made a wheat and the extra particles are causing issues with the refractometer, but I am not too sure if this is right or not. It is just a guess.
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Old 04-13-2009, 05:18 PM   #7
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There's a fair chance that your OG was lower than you thought. A 1.034 OG and a 5 Brix would corrdspond to the 1.011 SG you reported. A lot depends on how confident you are of the 1.048 OG number.


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