Is my hydrometer broken?

[PBRS1844]

Hello everyone,
I have had my hydrometer for about 4 years. It worked wonders for me but lately its been super strange. For the last three brews, I have gotten the exact same Post Boil Gravity as my Pre Boil Gravity, after allowing the reading to cool off to around 70. I boil-off around 1 gallon an hour. It boggles my mind that I could boil off a whole gallon and the gravity not change.
However, when I put the hydrometer in water it reads 1.000 and my beers finish around the 1.010.

P.s. I am also seeing some condensation at the bottom of the hydrometer. Not sure if that's fine or not.

Any input?

 

[VikeMan]

It boggles my mind that I could boil off a whole gallon and the gravity not change.

It's not possible. Are you sure you're taking both measurements at the same temperature, or correcting for temperature differences properly?

P.s. I am also seeing some condensation at the bottom of the hydrometer. Not sure if that's fine or not.

If there's anything inside that hasn't been there ever since the hydrometer was manufactured, then it must be cracked somewhere.

 

[PBRS1844]

It's not possible. Are you sure you're taking both measurements at the same temperature, or correcting for temperature differences properly?



If there's anything inside that hasn't been there ever since the hydrometer was manufactured, then it must be cracked somewhere.

Yea, I check temps and use the conversion tool on brewsmith, if needed, but never over 120 degrees.

 

[Qhrumphf]

Has anything else in your process changed in the last three brews? Particularly with changes to how you sparge or how you collect the sample?

It's easy to get a poorly mixed pre-boil gravity sample, and if you grab more early runnings than later runnings the pre-boil gravity can seem inflated as a result.

As said above, condensation/moisture collecting inside would indicate your hydrometer is damaged, which would also easily explain it. Though I find it odd that it'd still read normally in other situations.

 

[PBRS1844]

Nothing has changed in the last 5 years with my brews. I completely empty my running into my kettles then take my readings from there.

I did a different brew In new electric system and same exact thing. Pre and post are the same.

 

[Qhrumphf]

Does your hydrometer have a Brix scale? You can easily calibrate it that way. % by weight sucrose dissolved into distilled water will tell you Brix. So 10 grams table sugar with enough water for 100 total grams will be 10° Brix (or about 1.040). If you're looking in the 1.070 range, I'd check 15° Brix and and 20° Brix.

Assuming it's not a faulty hydrometer, you're almost assuredly not getting a homogeneous pre-boil sample. If you changed systems, that's what I mean by a change in your process.

Stir it well before taking your sample. Alternatively, my preferred method is to let it boil for a minute or two, then sample it. That does a decent job getting it homogeneous.

Running off in such a way that the wort is spinning in the kettle will do it a decent job as well- essentially pumping in at an angle as one would do whirlpooling.

 

[day_trippr]

fwiw, the PC term is "differently accurate"...

Cheers!

 

[Nate R]

Hello everyone,
I have had my hydrometer for about 4 years. It worked wonders for me but lately its been super strange. For the last three brews, I have gotten the exact same Post Boil Gravity as my Pre Boil Gravity, after allowing the reading to cool off to around 70. I boil-off around 1 gallon an hour. It boggles my mind that I could boil off a whole gallon and the gravity not change.
However, when I put the hydrometer in water it reads 1.000 and my beers finish around the 1.010.

P.s. I am also seeing some condensation at the bottom of the hydrometer. Not sure if that's fine or not.

Any input?

Have you always let it cool for the pre-boil the same way? I think i've read that pre-boil can still have a bit of evaporative loss which may effect your reading?

 

[TheMadKing]

Do you have a herms coil or an immersion chiller that might be leaking?

A number of years back I had a similar mystery and it turned out, I had a small leak on the water input into my immersion chiller, and the water was wicking along the underside of the copper and I couldn't see it at all. I finally figured it out by doing careful volume measurements.

So make sure you're double checking your volumes. If you're unknowingly adding water back at some point, then that would explain the issue also.