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General Category => General Homebrew Discussion => Topic started by: jth138 on February 04, 2011, 12:42:02 AM

Title: Trying to read a Hydrometer
Post by: jth138 on February 04, 2011, 12:42:02 AM
in a previous post i said i was brewing my first batch, well now i am finished and i don't know how to read this hydrometer.  the paper inside the tube was not very helpful.  can anyone help please?  thanks


http://s1118.photobucket.com/albums/k605/jth138/?action=view&current=gravity2.jpg (http://s1118.photobucket.com/albums/k605/jth138/?action=view&current=gravity2.jpg)

http://s1118.photobucket.com/albums/k605/jth138/?action=view&current=gravity2.jpg (http://s1118.photobucket.com/albums/k605/jth138/?action=view&current=gravity2.jpg)

http://s1118.photobucket.com/albums/k605/jth138/?action=view&current=gravity3.jpg (http://s1118.photobucket.com/albums/k605/jth138/?action=view&current=gravity3.jpg)
Title: Re: Trying to read a Hydrometer
Post by: jth138 on February 04, 2011, 12:44:01 AM
oops


http://s1118.photobucket.com/albums/k605/jth138/?action=view&current=gravity.jpg (http://s1118.photobucket.com/albums/k605/jth138/?action=view&current=gravity.jpg)
Title: Re: Trying to read a Hydrometer
Post by: Tim McManus on February 04, 2011, 12:52:40 AM
1.046
Title: Re: Trying to read a Hydrometer
Post by: kerneldustjacket on February 04, 2011, 12:53:10 AM
Looks like you've got about 1.046 there.

40 is the first number you can see above the liquid level; each line below the 40 is two gravity points.

When reading the hydrometer, you have to ignore the "meniscus," that little bit of liquid that "curves" up the side of the hydrometer, and look at the actual fluid level.        (http://en.wikipedia.org/wiki/Meniscus (http://en.wikipedia.org/wiki/Meniscus))

From your pic, it looks like the "actual" liquid level is about 3 lines below the 40 line...so 3 lines times 2 equals 6, plus the 40 makes 46. As a specific gravity you state that as "1.046."
Title: Re: Trying to read a Hydrometer
Post by: euge on February 04, 2011, 12:53:57 AM
Yup. That or 1.047  ;)
Title: Re: Trying to read a Hydrometer
Post by: jamminbrew on February 04, 2011, 12:57:43 AM
Looks like your starting gravity is 1.045, which puts you at 11.2 degrees plato. It also gives you a potential alcohol % by volume of 6 %, but that is only if you ferment back to a 1.000 gravity, which is near impossible with an average beer.  More likely, your final ABV % will be approx. 4 to 4.5 %.  
There's a lot of very knowledgable and experienced brewers on this forum, and I'm sure someone will explain it better than my humble self.
Title: Re: Trying to read a Hydrometer
Post by: jth138 on February 04, 2011, 12:59:33 AM
that helps a lot thanks for "dumbing" it down for me lol

so then the % side has a like and the first number i can see is 5 and across from that is 10, how do i read that appropriately ?
Title: Re: Trying to read a Hydrometer
Post by: jamminbrew on February 04, 2011, 01:08:01 AM
 10 is the degrees Plato, and the %5  is your potential alcohol by volume.
Title: Re: Trying to read a Hydrometer
Post by: richardt on February 04, 2011, 01:17:34 AM
In "Designing Great Beers" Ray Daniels says:  "(The hydrometer reading should be observed at the top of the small meniscus that forms around the hydometer shaft.)  While this might seem simple, I did it incorrectly for nearly six years!"  (page 14).

The SG looks like 1.045 if you read it that way.
Title: Re: Trying to read a Hydrometer
Post by: jth138 on February 04, 2011, 01:22:19 AM
thanks again, just 2 more questions

the kit said it should have an O.G. of 1.044 and mine is close to 1.046 is this a problem? 

what does the Plato mean? 

thanks again.  i really appreciate your time and knowledge
Title: Re: Trying to read a Hydrometer
Post by: Tim McManus on February 04, 2011, 01:29:10 AM
You probably have a triple scale hydrometer.  It allows you to measure the gravity of the wort in three different scales.  The one most home brewers use is the one that starts with 1.000 and goes down to the now debated 1.045, 1.046, and 1.047 numbers.

If you are a few points off, don't worry about it.  Many things can affect this number.  For now rest assured that you did everything correctly.  Close enough is good enough.

Plato is another scale to measure things.  Some brewers and wine makers use a Plato scale instead of the gravity scale referenced in your brewing kit.  It's similar to saying that 2.5 centimeters is one inch.  They measure the same length but using two different scales of measurement.
Title: Re: Trying to read a Hydrometer
Post by: Hokerer on February 04, 2011, 01:30:16 AM
1.044 and 1.046 are so close as to basically make no real noticeable difference.  And Plato is just another scale for measurement.  Think of it as sort of like Fahrenheit and Celsius for temperature (although not exactly equivalent).
Title: Re: Trying to read a Hydrometer
Post by: jth138 on February 04, 2011, 02:01:45 AM
thanks everyone for the advice/info you have all been a great help.


i gotta say, for a it taking a little while with the boil and everything it went extremely fast! 
i can not wait to taste this ale, and to make many, many more!
Title: Re: Trying to read a Hydrometer
Post by: bluesman on February 04, 2011, 02:12:47 AM
Looks like it's between 1.045 and 1.046. Probably 1.0455.  ;)

However you may perceive the reading, make sure you read it the same way every time for consistency in reporting your numbers. Plus or minus a point won't make a huge difference.
Title: Re: Trying to read a Hydrometer
Post by: oscarvan on February 04, 2011, 02:28:20 AM
1.04583477556

+/- .0000000001

Seriously, anything within .003 to .005 is fine in my book. DWHAHB Let 'er bubble away.
Title: Re: Trying to read a Hydrometer
Post by: bluesman on February 04, 2011, 02:32:59 AM
1.04583477556

+/- .0000000001

Seriously, anything within .003 to .005 is fine in my book. DWHAHB Let 'er bubble away.

You must have the digital scientific scale. I'm on the lookout for one of them.  ;)
Title: Re: Trying to read a Hydrometer
Post by: oscarvan on February 04, 2011, 02:37:42 AM
I could tell you where to get one...... but then I'd have to kill you.
Title: Re: Trying to read a Hydrometer
Post by: bluesman on February 04, 2011, 02:42:16 AM
I could tell you where to get one...... but then I'd have to kill you.

Well Oscar you're too late. I might need to take out a loan on this one.  :)

http://www.sbsbattery.com/subpage_index.php?_subp_=172

(http://www.sbsbattery.com/UserFiles/SBS-3500%20image.jpg)
Title: Re: Trying to read a Hydrometer
Post by: Hokerer on February 04, 2011, 02:57:41 AM
And now that you know how to visually read your hydrometer, there're two more things you need to do.  Number one is to look for the little chart that came with the hydrometer - that chart tells you how to correct the visual reading for the temperature of the wort you're measuring.  Number two is to go to the grocery store and get a jug of distilled water - use your hydrometer to measure it's gravity and, after correcting for temperature with the chart, it should read 1.000.  If it doesn't, you'll need to remember correct your readings for whatever error there might be.
Title: Re: Trying to read a Hydrometer
Post by: oscarvan on February 04, 2011, 03:11:50 AM
I could tell you where to get one...... but then I'd have to kill you.

Well Oscar you're too late. I might need to take out a loan on this one.  :)

http://www.sbsbattery.com/subpage_index.php?_subp_=172

(http://www.sbsbattery.com/UserFiles/SBS-3500%20image.jpg)

Oscillating Youtube technology..... I am in AWE!
Title: Re: Trying to read a Hydrometer
Post by: Tim McManus on February 04, 2011, 03:18:18 AM
I could tell you where to get one...... but then I'd have to kill you.

Well Oscar you're too late. I might need to take out a loan on this one.  :)

http://www.sbsbattery.com/subpage_index.php?_subp_=172

(http://www.sbsbattery.com/UserFiles/SBS-3500%20image.jpg)

Who's gonna' be the first person to click on the "Request Quote" link?  I want to know how much this thing costs.
Title: Re: Trying to read a Hydrometer
Post by: oscarvan on February 04, 2011, 03:21:21 AM
One MILLION dollars.....

(http://www.wildsound-filmmaking-feedback-events.com/images/austin_powers_dr_evil.jpg)
Title: Re: Trying to read a Hydrometer
Post by: punatic on February 04, 2011, 03:24:30 AM

what does the Plato mean? 


Plato (http://plato.stanford.edu/entries/plato/)
Title: Re: Trying to read a Hydrometer
Post by: morticaixavier on February 04, 2011, 03:32:25 AM

what does the Plato mean? 


Plato (http://plato.stanford.edu/entries/plato/)

Well that's who he was and what he thought but what did he mean?
Title: Re: Trying to read a Hydrometer
Post by: Tim McManus on February 04, 2011, 03:58:46 AM
I thought it was this (http://www.hasbro.com/playdoh/en_US/) (<-- That's a link).
Title: Re: Trying to read a Hydrometer
Post by: punatic on February 04, 2011, 06:10:45 AM
I thought it was this (http://www.hasbro.com/playdoh/en_US/) (<-- That's a link).

Naw, that's just Homer Simpson having fun Homer-style...   :D
Title: Re: Trying to read a Hydrometer
Post by: tschmidlin on February 04, 2011, 06:30:10 AM
In "Designing Great Beers" Ray Daniels says:  "(The hydrometer reading should be observed at the top of the small meniscus that forms around the hydometer shaft.)  While this might seem simple, I did it incorrectly for nearly six years!"  (page 14).

The SG looks like 1.045 if you read it that way.
I agree a couple of points either way doesn't make much of a difference, but read the above again - Ray only did it wrong for 6 years, I did it for much longer than that!  For a gravity reading you read from the TOP of the meniscus.  This is totally different from taking a volume reading, where you read the bottom of the meniscus.

I suspect it is designed this way because for a volume reading you read the marks on the outside of the vessel so the color and viscosity of the liquid make no difference.  For a gravity reading you read the marks off of something floating in the liquid, so the color/viscosity may make it harder to read the bottom, but you can look from the side and see where the top is.

But not that big of a deal either way.
Title: Re: Trying to read a Hydrometer
Post by: punatic on February 04, 2011, 02:33:18 PM
I use a class A volumetic flask and a scale with 0.001g resolution.  That is a direct measurement of density, not a correlation to buoyancy.  In this case I sight the reading across the bottom of the concave meniscus.
Title: Re: Trying to read a Hydrometer
Post by: tschmidlin on February 04, 2011, 05:30:04 PM
I use a class A volumetic flask and a scale with 0.001g resolution.  That is a direct measurement of density, not a correlation to buoyancy.  In this case I sight the reading across the bottom of the concave meniscus.
Use what you have :)
Title: Re: Trying to read a Hydrometer
Post by: oscarvan on February 04, 2011, 05:35:10 PM
I use a class A volumetic flask and a scale with 0.001g resolution.  That is a direct measurement of density, not a correlation to buoyancy.  In this case I sight the reading across the bottom of the concave meniscus.

And you find the average hydrometer off by how much? My guess is .002-.004
Title: Re: Trying to read a Hydrometer
Post by: Kaiser on February 04, 2011, 05:38:03 PM
When reading the hydrometer, you have to ignore the "meniscus," that little bit of liquid that "curves" up the side of the hydrometer, and look at the actual fluid level.

I found that this depends on the hydrometer. Mine for example reads calibration temperature water correct at 1.000 when I read the top of the meniscus.

Kai
Title: Re: Trying to read a Hydrometer
Post by: Slowbrew on February 04, 2011, 05:40:37 PM
When reading the hydrometer, you have to ignore the "meniscus," that little bit of liquid that "curves" up the side of the hydrometer, and look at the actual fluid level.

I found that this depends on the hydrometer. Mine for example reads calibration temperature water correct at 1.000 when I read the top of the meniscus.

Kai

The hydrometer I have at the moment reads .003 below actual.

Paul
Title: Re: Trying to read a Hydrometer
Post by: bluesman on February 04, 2011, 05:48:51 PM
One thing to take into consideration is calibration. When calibrating your hydrometer in distilled water at 60F take note of the reading and how you are taking your reading on the hydrometer. These two things are important for two reasons, one being a correction factor (if present) and secondly the way you are reading the hydrometer (above the liquid or at the meniscus). When using the hydrometer to measure the gravity of the wort make sure to apply the correction factor (if necessary) and take the reading the same way as was done during calibration.
Title: Re: Trying to read a Hydrometer
Post by: a10t2 on February 04, 2011, 06:02:29 PM
When calibrating your hydrometer in distilled water at 60F...

Assuming your hydrometer is calibrated at 60°F. ;)

The little slip of paper that came with the hydrometer will tell you the calibration temperature, and probably whether to read the top or bottom of the meniscus.
Title: Re: Trying to read a Hydrometer
Post by: bluesman on February 04, 2011, 06:07:41 PM
When calibrating your hydrometer in distilled water at 60F...

Assuming your hydrometer is calibrated at 60°F. ;)

The little slip of paper that came with the hydrometer will tell you the calibration temperature, and probably whether to read the top or bottom of the meniscus.

True, but I haven't come across one that wasn't...not that you're wrong. Just sayin.

Title: Re: Trying to read a Hydrometer
Post by: a10t2 on February 04, 2011, 06:10:40 PM
True, but I haven't come across one that wasn't...not that you're wrong. Just sayin.

Admittedly, I've only bought two of the typical homebrew-shop $8 models, but they were both calibrated at 20°C/68°F. Probably just different brands. The ones we have at the brewery are calibrated at 59°F.
Title: Re: Trying to read a Hydrometer
Post by: Kaiser on February 04, 2011, 06:12:00 PM
My hydrometer is a bit off as well, but I’m correcting for this and temperature, buy using a customized table like this. The customization allows it to account for the offset that you see when you read plain water:

http://www.braukaiser.com/documents/hydrometer_conversion_tables.pdf

I have one for the 0-30 Plato hydrometer and one for the 0.990 – 1.020 hydrometer on the front  and back of my brewing log book. When I take a reading I also take the sample temperature and find the corrected value that I then write into my notes.

Kai
Title: Re: Trying to read a Hydrometer
Post by: bluesman on February 04, 2011, 06:12:35 PM
True, but I haven't come across one that wasn't...not that you're wrong. Just sayin.

Admittedly, I've only bought two of the typical homebrew-shop $8 models, but they were both calibrated at 20°C/68°F. Probably just different brands.

You are correct in that there are different calibration temps for hydrometers. I think 60F and 68F are probably the most common for brewers and vintners.
Title: Re: Trying to read a Hydrometer
Post by: punatic on February 04, 2011, 06:31:11 PM
Just a thought...  how important are exact hydrometer readings?  Could you tell the difference in a beer with an original gravity reading of 1.048 that should have been 1.052?  Is an error of 0.004 gravity points significant?  Can $10 hydrometers be counted on to be accurate to 0.002 gravity points (the smallest graduation on most HB hydrometers)?

I know several brewers who brew by recipe only and never take specific gravity readings.  Their beers taste just as good, time after time, as any I've tasted where the O.G. and T.G. are known.  I kid them that their brewing is like driving a car without a speedometer.

I use the flask and scale method because I can and it's convenient.  I work with lab equipment daily.  More often I use it to calulate ethanol content.
Title: Re: Trying to read a Hydrometer
Post by: Kaiser on February 04, 2011, 06:40:43 PM
Just a thought...  how important are exact hydrometer readings?  Could you tell the difference in a beer with an original gravity reading of 1.048 that should have been 1.052?  Is an error of 0.004 gravity points significant?  Can $10 hydrometers be counted on to be accurate to 0.002 gravity points (the smallest graduation on most HB hydrometers)?

It think it is more important to have consistent hydrometer readings than it is to have precise readings. After all you want repeatability. Precise readings are nice to have if you want to exchange that data with other home brewers.

I think most hydrometers suffer from not being correctly calibrated to at the 1.000 mark. Once that is correct the only other thing that matters is the diameter of the tube with the scale. This will determine how far the hydrometer rises as the sugar content increases. I think that diameter might be fairly well controlled when they make the glass stock from which hydrometers are blown.

Kai
Title: Re: Trying to read a Hydrometer
Post by: bluesman on February 04, 2011, 06:46:25 PM
It think it is more important to have consistent hydrometer readings than it is to have precise readings. After all you want repeatability. Precise readings are nice to have if you want to exchange that data with other home brewers.

+1

Repeatability is key to understanding one's process variability. I also like to know how accurate my readings are as well so they are both important to me.
Title: Re: Trying to read a Hydrometer
Post by: Hokerer on February 04, 2011, 06:48:41 PM

The hydrometer I have at the moment reads .003 below actual.

Paul

Both of mine read .003 above actual.
Title: Re: Trying to read a Hydrometer
Post by: Janis on February 04, 2011, 07:05:04 PM
in a previous post i said i was brewing my first batch, well now i am finished and i don't know how to read this hydrometer.  the paper inside the tube was not very helpful.  can anyone help please?  thanks


http://s1118.photobucket.com/albums/k605/jth138/?action=view&current=gravity2.jpg (http://s1118.photobucket.com/albums/k605/jth138/?action=view&current=gravity2.jpg)

http://s1118.photobucket.com/albums/k605/jth138/?action=view&current=gravity2.jpg (http://s1118.photobucket.com/albums/k605/jth138/?action=view&current=gravity2.jpg)

http://s1118.photobucket.com/albums/k605/jth138/?action=view&current=gravity3.jpg (http://s1118.photobucket.com/albums/k605/jth138/?action=view&current=gravity3.jpg)

Hi,

You should check out the AHA Homebrewopedia for procedures like this.  There is a procedure called Specific Gravity Measurements (http://wiki.homebrewersassociation.org/SpecificGravityMeasurements (http://wiki.homebrewersassociation.org/SpecificGravityMeasurements)) that may help. 

Also, the AHA Homebrewopedia is a great way for homebrewers to pass on their expertise to those who are less experienced.  Check it out!

Cheers,
   Janis

Janis Gross
National Homebrew Competition Director
AHA Project Coordinator
janis@brewersassociation.org
Title: Re: Trying to read a Hydrometer
Post by: denny on February 04, 2011, 07:35:37 PM
THIS!  ^^^^^^^^^
Title: Re: Trying to read a Hydrometer
Post by: bluesman on February 04, 2011, 07:45:18 PM
THIS!  ^^^^^^^^^

+1

Thanks Janis...I learn something everyday here. I didn't realize there were instructions for this on the homebrewopedia.

I like to keep my hydrometer and thermometer together as I have forgotten to measure the temp of the wort prior to reading the hydrometer and the temp is required to correct the SG reading.
Title: Re: Trying to read a Hydrometer
Post by: euge on February 04, 2011, 07:46:12 PM
THIS!  ^^^^^^^^^

+1

Thanks Janis...I learn something everyday here. I didn't realize there was instructions for this on the homebrewopedia.

And it says to read from the bottom of the meniscus.
Title: Re: Trying to read a Hydrometer
Post by: punatic on February 04, 2011, 08:14:03 PM

It think it is more important to have consistent hydrometer readings than it is to have precise readings. After all you want repeatability. Precise readings are nice to have if you want to exchange that data with other home brewers.

Kai


I agree.  Precise (consistant) readings are good for repeatability.  Precision allows one to track changes despite inaccuracy.  However, accuracy is needed to exchange meaningful data with other homebrewers.

As a system operator I sometimes have to track process trends using precise online monitors, whose accuracy is out of calibration. 
Title: Re: Trying to read a Hydrometer
Post by: Janis on February 04, 2011, 08:27:06 PM
THIS!  ^^^^^^^^^

+1

Thanks Janis...I learn something everyday here. I didn't realize there were instructions for this on the homebrewopedia.

I like to keep my hydrometer and thermometer together as I have forgotten to measure the temp of the wort prior to reading the hydrometer and the temp is required to correct the SG reading.

Hi Ron,
No worries, glad to help. 

Actually, I thought there was a video demonstration on the AHA web site, but not yet.  I believe we're asking for volunteers to make videos of brewing procedures like this that we can post on our Videos page (http://www.homebrewersassociation.org/pages/community/videos (http://www.homebrewersassociation.org/pages/community/videos)).  Check out the call for Volunteers (http://www.homebrewersassociation.org/pages/membership/volunteer (http://www.homebrewersassociation.org/pages/membership/volunteer)).

Cheers,
   Janis