Author Topic: Refractometer Help for FG Reading  (Read 514 times)

Offline Lylebobyle

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Refractometer Help for FG Reading
« on: July 17, 2014, 06:23:53 AM »
My Wheat Pale Ale is done after 2 weeks in fermeneter. OG was 1.062.....FG Refractometer Brix reading is 8.5.

So, does this look correct below? ABV should be about 6%? Thanks....


Original Gravity: 1.062 SG   
FG - (Brix WRI):    8.5 Brix
Wort Correction Factor: 1   
     

OG - Corrected:    
15.21 °P, 1.062
FG - Corrected:    
4.29 °P, 1.017
Alcohol By Volume:    
6.17%

Offline Steve in TX

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Re: Refractometer Help for FG Reading
« Reply #1 on: July 17, 2014, 06:52:11 AM »
Refractometers cannot be used reliably to determine finishing gravity. Calculators online and in software will get you close, but in my experience they each give me a different result and it rarely matches my hydrometer.


I use a refractometer for small batches where getting a flask full is a waste, but I only rely on it to tell me when fermentation is finished, not where it finished. I then just assume it got to about where I wanted it.
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Online duboman

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Re: Refractometer Help for FG Reading
« Reply #2 on: July 17, 2014, 07:48:55 AM »

Refractometers cannot be used reliably to determine finishing gravity. Calculators online and in software will get you close, but in my experience they each give me a different result and it rarely matches my hydrometer.


I use a refractometer for small batches where getting a flask full is a waste, but I only rely on it to tell me when fermentation is finished, not where it finished. I then just assume it got to about where I wanted it.
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Offline HoosierBrew

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Re: Refractometer Help for FG Reading
« Reply #3 on: July 17, 2014, 07:55:10 AM »
+2  -  Refractometer for pre and post boil, hydrometer for FG for me.
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Offline Jeff M

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Offline morticaixavier

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Re: Refractometer Help for FG Reading
« Reply #5 on: July 17, 2014, 07:56:20 AM »
http://seanterrill.com/2012/01/06/refractometer-calculator/

this one does seem to work best for me. you still have to use your hydrometer to figure out your correction factor but once you have that it's pretty accurate.

Offline Lylebobyle

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Re: Refractometer Help for FG Reading
« Reply #6 on: July 17, 2014, 08:53:31 AM »
But what I have looks ok for a relatively acurate ABV reading?

Offline Jeff M

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Re: Refractometer Help for FG Reading
« Reply #7 on: July 17, 2014, 09:23:11 AM »
Without a grainbill and yeast used its kinda tough to say if you are close or not.
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Offline Steve in TX

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Re: Refractometer Help for FG Reading
« Reply #8 on: July 17, 2014, 09:44:56 AM »
That would be about 73% attenuation, so it could be. All depends on what you were going for. I rarely have beers that finish that high.
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Offline ynotbrusum

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Re: Refractometer Help for FG Reading
« Reply #9 on: July 17, 2014, 11:17:56 AM »
I can see a wheat beer finishing in that range.  But if you have a hydrometer available, I would use it and see how close you came with the refractometer and Sean's spreadsheet.

That spreadsheet is pretty good, but IIRC, with lower OG beers, it can be a bit off. You had a plenty big beer, so it should be pretty accurate over time by entering you hydrometer readings for a few beers in this range.
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Offline Lylebobyle

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Re: Refractometer Help for FG Reading
« Reply #10 on: July 17, 2014, 06:49:37 PM »
Thank you all for the help....I kegged today. The wort tasted great! It was a Wheat Ale using Amarillo and my own home-grown Chinook Hops.

Offline ynotbrusum

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Re: Refractometer Help for FG Reading
« Reply #11 on: July 17, 2014, 06:56:28 PM »
Thank you all for the help....I kegged today. The wort tasted great! It was a Wheat Ale using Amarillo and my own home-grown Chinook Hops.

Except you kegged beer, not wort! Congrats.
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Offline Lylebobyle

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Re: Refractometer Help for FG Reading
« Reply #12 on: July 17, 2014, 07:05:03 PM »
Thank you all for the help....I kegged today. The wort tasted great! It was a Wheat Ale using Amarillo and my own home-grown Chinook Hops.

Except you kegged beer, not wort! Congrats.

Whoops...yes, very true...lol

Offline brewinhard

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Re: Refractometer Help for FG Reading
« Reply #13 on: July 18, 2014, 01:23:34 PM »
Refractometers can also be good for determining when fermentation is complete as well.  If readings are taken throughout the primary fermentation (a bonus since only a drop is needed), one can track the gravity dropping until terminal gravity has been reached (which can easily be indicated with a refractometer reading of no change over several days).  Do keep in mind as stated above many of the formulas are not quite effective for actual measurements once alcohol is produced during fermentation, so you are really better off utilizing a hydrometer to measure your final gravity correctly.