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Old 05-02-2012, 11:13 PM   #1
kevinb's Avatar
Mar 2012
, MA
Posts: 653
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My wife bought me a refractometer for my birthday today (yes I have a great wife). I typically extract brew. However, I like the idea of being able to use a couple drops of wort to make a measurement.

I have seen other posts that say they are only accurate before fermentation because of the alcohol after fermentation. Does the Excel spreadsheet on more beer work for FG correction ? Is it accurate? Does anyone else have a conversion that they can tell me about?

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Old 05-02-2012, 11:16 PM   #2
Mar 2010
St. Louis
Posts: 134
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I use this site to correct for alcohol.

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Old 05-02-2012, 11:28 PM   #3
Sep 2010
Las Vegas
Posts: 651
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I use mine during fermentation and after it's done and with the gravity correction its pretty accurate. If I am really really curious I will take a FG reading with a hydrometer. If you have an android phone the brewzor calculator is a great app and includes a refractometer gravity correction tool.

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Old 05-02-2012, 11:30 PM   #4
Dec 2011
Posts: 10

Most applications can accept a FG reading from a refractometer as well. It is accurate as long as the correction formula is used.

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Old 05-03-2012, 12:06 AM   #5
Sacdan's Avatar
Jul 2009
Sacramento, CA
Posts: 888
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Originally Posted by lestershy View Post
I use this site to correct for alcohol.
+1 I use this site as well.

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Old 05-03-2012, 12:16 AM   #6
Feb 2012
Will County, Illinois
Posts: 241
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I've used the morebeer spreadsheet and it seems to work fine. I do take both a refract and hydrometer reading before pitching yeast, then let the spreadsheet do the work after based on refract. I did check the first few readings both ways and it worked fine.

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Old 05-03-2012, 12:22 AM   #7
Zen_Brew's Avatar
May 2009
Posts: 1,864
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Some more food for thought. Sean Terrill did a series of experiments to verify common refractometer correction curves and made some adjustments to the common curve. In my experience with it, I find his spreadsheet to correct for readings I used to get that were too low.
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Old 05-03-2012, 01:54 AM   #8
Marquez's Avatar
Aug 2008
Littleton CO
Posts: 359
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I use this one:

Look here for more information about it:

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Old 05-03-2012, 01:58 AM   #9
Johnnyhitch1's Avatar
Dec 2011
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Originally Posted by lestershy View Post
I use this site to correct for alcohol.
+1 on this for sure

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Old 02-04-2014, 04:19 PM   #10
Sep 2010
columbus, oh
Posts: 1,129
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I found both Sean Terrill's calculator and the brewers friend to be very close to my actual hydrometer readings (.002 SG points less than actual hydrometer readings).

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