Author Topic: Help interpreting hydrometer readings  (Read 1077 times)

Offline Bevilaquafoto

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Help interpreting hydrometer readings
« on: November 01, 2014, 02:33:47 PM »
Hello, everyone. I am new to the forum, and have been home brewing for about a year now. I don't know if it's just me, or if this is a common issue, but I have a really tough time reading my hydrometer with it's tiny lines, and also trying to decipher what is above the meniscus and what is right at water/wort level. Would anyone be willing to look at two pictures and offer their judgement as to what the correct reading is? Do other people find it difficult to read a hydrometer? Is anyone using a refractometer? Am I trying too hard with this?
Lorenzo Bevilaqua
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Offline Bevilaquafoto

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Re: Help interpreting hydrometer readings
« Reply #1 on: November 01, 2014, 02:39:04 PM »
I don't seem to be able to post attachments yet. Working on it now.
« Last Edit: November 01, 2014, 02:50:13 PM by Bevilaquafoto »
Lorenzo Bevilaqua
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302A West 12th Street
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Offline reverseapachemaster

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Re: Help interpreting hydrometer readings
« Reply #2 on: November 01, 2014, 02:54:01 PM »
It's definitely not the easiest task and we're all just eyeballing it. You will have the same issue with a refractometer. You're still just judging small lines against another line. My suggestion is pick a way of reading the hydrometer and stick to it. It doesn't really matter whether you are reading 1.011 or 1.012 but the inaccuracy of your readings will be a lot lower if you use the same visual standard for OG and FG.
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Offline Bevilaquafoto

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Re: Help interpreting hydrometer readings
« Reply #3 on: November 01, 2014, 02:59:55 PM »
Thank you! That's what I was thinking. It seemed to make sense that as long as I kept to a visual standard, and could see the progression of high OG to a low FG, and could judge if fermentation had completed, that I was in good shape. I'm always within a couple of points on the hydrometer.
Lorenzo Bevilaqua
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302A West 12th Street
Suite 245
New York, NY 10014
http://www.lorenzobevilaqua.com
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Offline klickitat jim

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Re: Help interpreting hydrometer readings
« Reply #4 on: November 02, 2014, 01:44:31 AM »
I always go by what is above liquid including the little ramp against the glass, that way I always err on the high side. But ya just do it the same every time.

Offline HoosierBrew

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Re: Help interpreting hydrometer readings
« Reply #5 on: November 02, 2014, 01:55:09 AM »
It's definitely not the easiest task and we're all just eyeballing it. You will have the same issue with a refractometer. You're still just judging small lines against another line. My suggestion is pick a way of reading the hydrometer and stick to it. It doesn't really matter whether you are reading 1.011 or 1.012 but the inaccuracy of your readings will be a lot lower if you use the same visual standard for OG and FG.

+1
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Offline ynotbrusum

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Re: Help interpreting hydrometer readings
« Reply #6 on: November 02, 2014, 11:53:04 AM »
One thing in addition to the foregoing - calibrate your hydrometer at the temperature it is rated at - I have one that reads 3 points lower than actual.  So I kept getting low readings for Gravity and wondered why until I put some distilled water at 68F and found the issue...


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Re: Help interpreting hydrometer readings
« Reply #7 on: November 02, 2014, 04:40:02 PM »
I can't imagine brewing without a refractometer (for all-grain), but it won't give you substantially better precision than a decent hydrometer. No matter the instrument, calibration is key. Top/bottom of the meniscus, calibration temperature, etc. vary from one manufacturer to the next. No need to use distilled water, though - you can't measure the difference in density vs. tap water.
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Offline Bevilaquafoto

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Re: Help interpreting hydrometer readings
« Reply #8 on: November 03, 2014, 01:08:03 PM »
Thank you all for the very helpful responses. I have the standard long, multicolored hydrometer that your local brewshop carries, in my case it's Bitter & Esters in Brooklyn New York. I don't remember what the temperature is supposed to be for water to record gravity at 1.000. I think it's 68 degrees. I never actually thought about calibrating my hydrometer, and will do that today. The idea of using a consistent method of reading makes a great deal of sense. Even if the reading is off by a line, if the original and final gravity readings are made using the same method, then you can determine ABV, and whether or not your wort has fully attenuated.

Thanks for the help!
Lorenzo Bevilaqua
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Offline tress

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Re: Help interpreting hydrometer readings
« Reply #9 on: November 03, 2014, 03:31:24 PM »
Also, immediately after taking the SG reading of the final wort volume with your hydrometer, record the temperature of the wort.  Check the calibration temperature on the slip of paper inside the hydrometer.  If the temperature of the wort at the time of the gravity reading is not at this calibrated temperature, your SG reading will need to be adjusted for this temperature change.  Brewing software (like Beersmith 2) will have a built-in tool to calculate the adjustment but I am sure Google will find you a free source.
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