Hydrometer Testing..

[sluggerdog]

Is there any simple way to test your hydrometer?

Maybe someway with water?

I ask as I am getting some low efficiency readings and I have just put this down to only starting out with AG brewing however my last few brews with the low efficiency and starting gravity are also finishing with a low gravity too..

eg:

BREW 1:

EST OG: 1048
EST FG: 1012

ACTUAL OG: 1046
ACTUAL FG: 1008


BREW 2:

EST OG: 1053
EST FG: 1015

ACTUAL OG: 1045
ACTUAL FG: 1009

Notice the differance between the EST gravities and ACTUAL gravities is about the same and always lower which I thought that maybe my hydrometer could be these few points out (approx 4-5 points higher then readings)

 

[sosman]

Is there any simple way to test your hydrometer?

[post="64119"][/post]​

Yes. Water at hydrometer calibration temperature (typically 20 C) should be 1.000.

You should be able to measure out some sugar solutions and then calibrate at other points. My notes tell me table sugar has an HWE of 384 points/kg/L. Assuming this is correct, adding 100 g of sugar to 1 L of water should yield a solution of 1.0384 points.

I have never tried this myself but my brewing process relies on facts like this.

 

[jgriffin]

If you test with plain water at 16C, then it should read 1.000
Reading with 100g of sugar disolvd in 1L of water at 16C should read 1.038

 

[sluggerdog]

I did a quick test with water and I found the following: (mine hydrometer is calebrated at 20C)

Water at 26C measured 0.960

How can I tell from this?

 

[sosman]

I did a quick test with water and I found the following: (mine hydrometer is calebrated at 20C)

Water at 26C measured 0.960

How can I tell from this?

[post="64124"][/post]​

You could try http://metrak.com/cgi-bin/sgform.py. I ran a check and it looks like it is reading a little low.

 

[pint of lager]

Get some water at 20 degrees and recheck the value shown. The right temperature is very important. Also, use good quality rain water, if your tap water is full of dissolved salts, this may throw the reading out.

If your hydrometer still shows as being out by a few points, you can add or subtract this error amount for each reading.

I have heard of some hydrometers, the little piece of paper in the stem is held by glue, the glue fails and the paper slipps in the stem causing incorrect readings.

Back to efficiencies, which I think is the crux of your problem. New ag brewers have poor efficiencies. Do not worry about this. Next time, bump up the amount of grain you are using so you achieve your expected gravities.

You should be aiming to perfect your brewing process, get the mash temp right, get the sparge right, get the boil right, get the cooling right, get the yeast pitching right, get the ferment temperature right, get your sanitation right, before worrying about achieving the same efficiency as someone else does. If you are using brewing software, just adjust your efficiency down.