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refractormeter and knowing when fermentation is done

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wisenuts

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Apr 11, 2017
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Saint Joseph
Got a new fancy refractometer, and while i know that the reading needs to be adjusted in the presence of alcohol if it reads the same for three days is my fermentation complete?

DUH: spelling in thread title...
 
Final gravity is better read with a Hydrometer, but you can use a refractometer with adjustments.

Can you provide more details on your grain bill, yeast, fermentation time, fermentation temperature, etc.?
 
Northern Brewer has a calculator on their site to make the adjustments for final gravity.
 
Got a new fancy refractometer, and while i know that the reading needs to be adjusted in the presence of alcohol if it reads the same for three days is my fermentation complete?

DUH: spelling in thread title...

Typically if you see stability for 3 days fermentation may be completed. You are correct that your refractometer reading will need to be adjusted with an online calculator if alcohol is present. I have also discovered the BRIX scale (if yours has both BRIX and SG) seems more accurate. I use a digital refractometer that reads in BRIX only so I am used to the conversion although I generally think in terms of Specific Gravity points.

You may choose a different approach, but I like to leave my beer in primary for two weeks (typically) to allow the yeast to settle down and clean itself of some off flavors. I have pushed it quicker than that of course just to test, and I feel the beer that I let alone for two weeks has a smoother more rounded profile. Others may feel differently, so you may want to try for yourself.
 
Yeah there's no issue with using the refrac to see when gravity has stopped dropping. Stable gravity doesn't mean that fermentation is complete though, yeast are still cleaning up the beer and precursors are breaking down into diacetyl then being absorbed by the yeast. Fermentation is complete when the yeast have cleaned up the beer and no precursor remains, refracs and hydrometers cannot tell you that. As a general rule I do primary 3-4 weeks before I package, the beer turns out great and I see no need to rush it.
 
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