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Refractometers and residual sugar measurement

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joet
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beers 2409 º places 100 º 12:53 Sat 11/17/2012

What are best practices for getting most accurate residual sugar readings with a refractometer and a known final gravity?

Are there any big caveats or known conditions that problematize results?

 
Quasimodo
beers 217 º 15:09 Sat 11/17/2012

Not sure how you would do that, but one thing to keep in mind is a refractometer doesnít give an accurate reading with the presence of alcohol.

 
bitbucket
beers 2160 º places 63 º 18:46 Sat 11/17/2012

Originally posted by Quasimodo
Not sure how you would do that, but one thing to keep in mind is a refractometer doesnít give an accurate reading with the presence of alcohol.

Not true. They just donít give the SAME reading with the presence of alcohol as without.

You canít get an accurate FG measurement without a known OG measurement, but if you have both you can do an accurate refractometer alcohol correction to determine the actual FG value.

 
Quasimodo
beers 217 º 18:52 Sat 11/17/2012

Yes, I know, but didnít assume the OP knew that and he already knows the FG. If he didnít, a hydrometer is the most accurate tool to use.

Do you know how to calculate residual sugar in a finished beer? I donít and thatís what he wants to know.

 
lithy
beers 2996 º places 156 º 19:00 Sat 11/17/2012

Use this spreadsheet to compensate for the change in readings due to the presence of ethanol.

http://morebeer.com/web_files/morebeer.com/files/THJ%20Refractometer_Beer.xls

Then reference this thread for some info on determining residual sugar content.

http://www.ratebeer.com/forums/hydrometer-alcohol-correction_213593.htm

 
Quasimodo
beers 217 º 19:15 Sat 11/17/2012

Originally posted by lithy
Use this spreadsheet to compensate for the change in readings due to the presence of ethanol.

http://morebeer.com/web_files/morebeer.com/files/THJ%20Refractometer_Beer.xls

Then reference this thread for some info on determining residual sugar content.

http://www.ratebeer.com/forums/hydrometer-alcohol-correction_213593.htm


Good answer!

 
joet
premium
admin
beers 2409 º places 100 º 00:02 Sun 11/18/2012

So I probably need a photometer then if I just have FG, weight, volume, temp, refractometer reading and abv?

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