Hydrometer Issues

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Hydrometer Issues

Postby Ben Bythewood » Tue Feb 27, 2007 11:21 am


I am an extract brewer and have done about 5 or 6 batches to this point. From the beggining the Hydrometer which I have been using has given me unexpected readings, often .01-.02 different than what I would expect. Its not too big of a problem in extract brewing and the beer has come out great, so it hasnt given me much cause for concern. I recently realized that I could test the hydrometer by putting it in water (approxmately 60 degrees no more than +/- 10). In water it was reading .0990. I have been using the tube the hydrometer came in to measure in (which is slightly larger than the hydrometer and allows for it to float). Do I just have a bad hydrometer or am I doing something wrong? At the homebrew store the guy told me that the hydrometer is supposed to read .0990 in water, but everywhere I have read says it should be 1.00. Thanks for the help.

Ben Bythewood
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Re: Hydrometer Issues

Postby billvelek » Tue Feb 27, 2007 12:41 pm

Ben Bythewood wrote:snip ... I recently realized that I could test the hydrometer by putting it in water (approxmately 60 degrees no more than +/- 10). ... snip
Are you saying the range of temp can be 50 to 70 F? That's not correct; you need to get as close to the proper temp as you can get, and ten degrees is way too much leeway. Also you might want to check your hydrometer because I suppose the calibration temp could possibly vary, although I think 60F is typical. Calibration temp should be printed on the slip of paper inside the hydrometer, probably near the bottom of the scale; mine is there and says "T 60F". Anyway, you should ensure your thermometer is accurate (calibrate it if you haven't by checking for 32F in an ice slush that has been melting in the refrigerator for awhile but is still mostly ice, and then for 212F in boiling water, and make any adjustments for altitude -- info available on internet). If freezing and boiling temps are off on your thermometer, I think it is usually safe to extrapolate on the scale, and determine where 60F should be; maybe it will be 61F on your themometer, etc. Use "DISTILLED" water and get it as close to your 60F equivalent as you can, and be sure to spin the hydrometer to rid it of any bubbles that might cling to the surface and add bouyancy. Be sure you read at the bottom of the meniscus -- where the water curves up the side of the hydrometer due to surface tension. As far as I know. what I've just told you is the correct way to calibrate; that's what I did when I first got my equipment. Good luck.


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