Calibrating my Hydrometer - Home Brew Forums

 Home Brew Forums > Calibrating my Hydrometer

04-02-2009, 02:04 PM   #1
TexasSpartan
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Jan 2009
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I'm just an extract brewer, and my OG and FG readings are always a little off. Never enough that I feel the need to ask if I've ruined my beer, but they're not what they should be.

I checked my hydrometer, and it says it is calibrated for 60 degrees. Look, I live in Texas. My house is never 60 degrees. The kitchen is usually closer to 70-75 when I'm brewing. And more importantly, my beer is usually at 70 or so when I'm pitching the yeast or taking a reading for the FG. So how do I adjust for temperature?

My thought was this, and please correct me if I'm wrong. Get some distilled water and let it warm up to room temperature. Drop the hydrometer and see what it reads. At 60 degrees it should read 1.000, correct? So if it read 0.998 (for example) at 70 degrees, I would add 0.002 to whatever reading I got.

Am I on the right track, or way off base?
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04-02-2009, 02:07 PM   #2
Nugu
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Mar 2009
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There's an equation you can plug it into I think. Unfortunately I don't know it (undoubtedly someone will enlighten us though) but ya that would work assuming you always took the reading at 70F.

I generally leave close enough as close enough. (we're talking it being off at most like .002
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04-02-2009, 02:26 PM   #3
david_42

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The correction varies with temperature and gravity, but the simplest thing it to check your hydrometer a 60F, then at 70F. Shouldn't be more than 0.002 delta.
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04-02-2009, 02:59 PM   #4
McKBrew

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Oct 2006
Hayden, Idaho
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There are several free applications on the internet that will do the conversion for you.
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04-02-2009, 05:30 PM   #5
eljefebrewing

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Mar 2009
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Look in Appendix I (I think) on howtobrew.com. Nice table there.

04-02-2009, 06:04 PM   #6
bull8042
I like 'em shaved

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Jul 2008
Fort Mill, SC
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BeerSmith also has a correction tool that requires you to enter the temp of the sample and the reading and it will give the corrected value.
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04-02-2009, 06:46 PM   #7
shawnbou
Zyme Lord

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Mar 2009
Austin, Texas
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I'm very new to this myself, but as a fellow Texan I can relate to your problems getting your house down to 60F!

My hydrometer reads accurately at 68F, so I think it may just vary from one hydrometer to another. Mine did come with a handy chart, though, for corrections due to temperature. I add .001 for every 9 degrees over 68, and subtract .001 for every 9 degrees under 68 ... the concept here being that warmer liquids are thinner and therefore will have a higher SG when they get to room temp, and vice versa.

Hope that helps. It sounds like you're on the right track.

04-02-2009, 09:15 PM   #8
steelerguy
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Apr 2008
Stony Brook, NY
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Here ya go:

The Beer Recipator - Hydrometer Correction

04-03-2009, 03:02 AM   #9
TexasSpartan
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Dallas, TX
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Quote:
 Originally Posted by steelerguy Here ya go: The Beer Recipator - Hydrometer Correction (This is assuming your hydrometer reads correctly at the calibrated temp)
Thanks
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