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Formula to correct SG for temp
Posted: Friday Jul 07, 2006 2:33 pm
by Wally
I am looking for the formula to correct the SG for temperature variations. It needs to be for a hydrometer which has been calibrated at 20 deg C. It can be complicated since I will be using it in a spreadsheet. At this point I could only get one that corrects for a calibration temp of 60 deg F.
Wally
Posted: Friday Jul 07, 2006 2:58 pm
by TommyH
Courtesy of Oliver
Posted: Friday Apr 01, 2005 12:58 am Post subject:
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The corrections should have come with the hydrometer.
Here are the corrections for a hydrometer calibrated to 20C:
Code:
Temp(C) Correction
4-10 -2
11-17 -1
18-22 0
23-26 +1
27-29 +2
30-32 +3
33-35 +4
36-38 +5
49-41 +6
So let's say that your wort was 27C when you took the reading of 1035/36. Therefore, the corrected reading is 1037/38.
Cheers,
Oliver
Posted: Friday Jul 07, 2006 2:58 pm
by DJ
someone had a link on here to a speadsheet that had it..
Ill have a search..
Posted: Friday Jul 07, 2006 4:27 pm
by Wally
Thanks for the quick replies, but I am looking for the mathematical formula to enable me to use it in a spreadsheet.
Posted: Friday Jul 07, 2006 5:46 pm
by Ed
This should be right, I use it in my spreadsheet. I just set up a conversion in another column to take the recorded temp in *C to *F to allow the formula to work.
To conver *C to *F
*F=(DC*1.8 )+32
Where DC is temp *C
Correction
Correction=(1.313454 - 0.132674*T + 0.002057793*T*T - 0.000002627634*T*T*T)/1000
Where T is temperature in *F
The resulting figure is the correction. Add that to the recorded gravity.
Cheers, Ed