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Old 02-16-2012, 01:37 PM   #1
Feb 2012
Posts: 105
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I understand that you can't use a refractometer on fermented wort. Is there a formula that will compensate for the alcohol?

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Old 02-16-2012, 03:08 PM   #2
Haputanlas's Avatar
Jan 2010
Austin, TX
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If you don't know the OG, you won't know the alcohol. However, I assume it would be possible to figure out the OG if you had the FG and the ABV.
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Old 02-16-2012, 03:15 PM   #3
Oct 2010
Posts: 159
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There is a formula thAt allows you to measure fermenting wort. I however don't know it since I use 'beer smith' which has a function for that. I have heard that it isn't very accurate, though. I always use a hydro once yeast has been pitched.

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Old 02-16-2012, 03:40 PM   #4
Registered User
Jan 2012
Posts: 16

The formula is:

Current Gravity = 1.53 X Current_Refractometer_Reading - 0.59 X Original_Gravity

OG will have to be expressed in degrees Brix (or Plato, whatever unit your refractometer uses) too!



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Old 02-16-2012, 04:48 PM   #5
Jun 2008
Tacoma, Wa
Posts: 459
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Just google refractometer calculator. I've used my refractometer for a year now. It is very accurate and allows for constant testing of the beer with minimal risk. I pulled hydro samples the first 6-7 batches to verify its accuracy. Make sure you account for temperature on both OG and FG, it makes a difference.

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Old 02-16-2012, 04:52 PM   #6
kh54s10's Avatar
Aug 2011
Tiverton, Rhode Island
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I ahve used a couple of calculators that I found by googling. They gave ma an idea of what the gravity was post fermentation but I didn't find them to be terribly accurate.

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Old 02-16-2012, 05:41 PM   #7
Spartan1979's Avatar
Feb 2011
O'Fallon, MO
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I've found the calculators to be fairly accurate, usually within a couple of points. I just use mine to give me an idea of where I'm at. I take the "official" FG reading with a hydrometer.

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Old 02-16-2012, 07:09 PM   #8
May 2011
Lockport, Illinois
Posts: 226
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The app "Brew Pal" has the alcohol correction for refractometer's and hydrometer corrections, amongst other goodies! I use an iPhone, don't know about Android or Blackberry.

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Old 02-17-2012, 11:15 AM   #9
RoadKing's Avatar
Oct 2005
Bayville, N.J.
Posts: 480
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I use this spreadsheet from Morebeer
The link to Download in under video. I know alot of people say it's not accurate with alcohol present, but when I double check it against hydrometer its allways correct.

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