Post-gravity reading CO2 purge prior to lagering?

Discussion in 'General Brewing Discussions' started by Virwill, Apr 18, 2020.

  1. Virwill

    Virwill New Member

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    Hope this finds everyone safe, fed and healthy. I need some process advice. I'm using a lager yeast (Imperial Global) in a Baltic Porter, fermenting at 53º and now at nearly 4 weeks. It was a good-looking fermentation. Now, I want to take gravity readings to be sure it's at my target before I a.) raise it to 56º for a few days of diacetyl rest and then b.) gradually drop it down to 35º (the advice of the folks at Imperial) for 6 weeks. I'm doing everything in primary, using a cylindro conical fermenter (The Catalyst). But I have yet to install a sample port. As much work/time as this little experiment is requiring, I don't want to potentially screw this up by introducing too much O2 before starting to lager. I'll draw my samples out of the blowhole, replacing the plug each time of course. If this was your batch and given that fermentation is probably nearly done, would you a.) assume it's close enough and not sample; b.) sample and don't worry about it; or c.) purge with CO2 after each gravity reading (assuming I only need two) before moving ahead? I don't have a CO2 setup and probably wouldn't use it enough at this point in my brewing to justify buying a 5-gal. tank. So if the consensus is that I should purge, I'll probably just bottle after the rest, install a port and sample things that way next time. Thoughts, please?
     
  2. Mark Farrall

    Mark Farrall Well-Known Member

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    As you don't have a CO2 setup I'd go with B. I have a CO2 setup and if I didn't have a sample port like you I'd still go with B. Baltic porter can generally tolerate some oxidation, though you'd prefer it to come later if you could avoid it.
     
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  3. Virwill

    Virwill New Member

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    Thanks, Mark. Nice hat(s).
     
  4. Virwill

    Virwill New Member

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    Mark, just occurred to me. I removed 3 jars of trub at the outset but still have more to go. In your lagering experience, should I try to get the rest of what's settled out of there before I start to cool it down?
     
  5. Mark Farrall

    Mark Farrall Well-Known Member

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    There's others with lots more experience lagering the me, but I see it as a question of what's the more likely with your setup. Can dump your dump your trub without much oxidation vs the chances of the trub creating off flavours. Traditionally the trub creating off flavours was mainly yeast autolysis, but that's harder to do with better yeast at the homebrew level.

    Looking at the fermenter you're using, I'd imagine you could dump fairly safely (and your dump will also give you a sample if it happens at the right time).
     
  6. Nosybear

    Nosybear Well-Known Member

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    Leave it, have a homebrew, relax. The trub won't hurt anything. You are more likely to damage your beer by messing with it than by leaving it on the trub. Yeast autolysis takes months at lager temps. Hop debris buried under yeast can't add off flavors to your beer. The lipids and proteins are flavorless. RDWHAHB.
     

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