Liquored back and OG stayed the same?

Discussion in 'General Brewing Discussions' started by Beer Foundry, May 16, 2020.

  1. Beer Foundry

    Beer Foundry New Member

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    I brewed a Kellerbier today, using a Brewer's Friend Community recipe. I think my measurements were a bit out as instead of an OG of 1.054 I got 1.066 but slightly too low on the volume.

    No problem I thought, I'll just liquor it back and there will be more to go round. So I added 3L boiled water (put through the counterflow chiller) to bring 22L to 25L and expected the OG to drop from 1.066 to 1.058. Took another sample and it was still reading 1.066 (using the hydrometer).

    How come?

    Does the wort settle in strata with the denser stuff at the bottom? I'd only just filled the FV from the counterflow chiller and it was falling from a reasonable height to get the oxygen incorporated, so presumed it was well mixed.

    Anyone else had something similar?
     
  2. Ward Chillington

    Ward Chillington Well-Known Member

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    Hey, welcome to the forum ….I dig that avatar!

    So I see you mentioned cooling the extra couple of liters you added but was what you measured with your Hydrometer the right temp for the meter or did you calculate for measurement to be different from what your hydrometer was designed for?
     
  3. Beer Foundry

    Beer Foundry New Member

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    I measured the gravity at 20 deg C both times, hence why I was puzzled.

    Thanks for the welcome.

    The avatar by the way is for my little brewing syndicate. There’s about 10 of us, each with a 5L mini keg from Dark Farms. About half of the 10 work at a local foundry where I help out, hence the name.

    Check us out on Instagram as beerfoundryuk. You can see photos of the set up on there.
     
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  4. Ward Chillington

    Ward Chillington Well-Known Member

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    OK...that rules that out...call in the smart people!
     
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  5. Beer Foundry

    Beer Foundry New Member

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    I was interested in the possibility of different density layers remaining stratified and not diffusing. This kids science video on YouTube probably answers my question.



    In which case, watch out for errors when taking samples from deep down in a conical surely?

    I wonder if it all evens out after a few days?
     
  6. J A

    J A Well-Known Member

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    I'd wonder about the hydrometer bottoming out. It's not physically possible to add water and have the same gravity.
     
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  7. Beer Foundry

    Beer Foundry New Member

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    That would certainly cause it JA, but it definitely floated - oscillating up and down until it settled on a reading.

    I think the density stratification theory is currently my favourite. Adding water to the top of a dense liquid and then taking a sample from the bottom where it remains unaffected (initially anyway). The you tube video explains it well.

    The reason I have never noticed this before is that I have only just fitted a sample-take off-tap at the bottom of my fast ferment conical. I also don’t usually liquor back.

    Just interested to see how many others have noticed the same.
     
  8. Beer Foundry

    Beer Foundry New Member

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    Quick update. Fermentation hasn’t really started yet (lager yeast and at 14°C). So I’ve just taken another sample and it is now down to 1.060 which is much closer to where it should have been.

    I think diffusion must have now done its job.
     

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