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Hop flavour gone after 1 day in keg

Discussion in 'Gear and Equipment' started by brewermp, 10/7/19.

 

  1. Smokomark

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    Posted 12/7/19
    What do you mean O2 based sanitizer. I have been filling my kegs with starsan and co2 purging for a few years now and noticed improvements/better consistincy since.
     
  2. MHB

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    Posted 12/7/19
    Any of the Peroxide based sanitiser or even Sodium Percarbonate (I hope no one would by using that as a final rinse sanitiser).
    At work we use Peroxitane to sanitise fermenters before wort is pumped up, home brewers use quite a lot of the shield (peroxide/silver) products, would be pretty silly to use a sanitiser that produces Oxygen when you are trying to minimise O2 exposure.
    StarSan isn't peroxide based if that helps.
    Mark
     
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  3. TheSumOfAllBeers

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    Posted 12/7/19
    This.

    I remember seeing a report from a us brewery, that the co2 purge only merely diluted the o2 in the keg - you need to use a lot more gas than you think to bring the o2 levels down to something safe.

    What’s safe for a lager may not be safe for an NE IPA

    Liquid purge is the way to go. You also need to purge your lines
     
  4. Smokomark

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    Posted 12/7/19
    Cheers Mark, just wanted to confirm I was doing the right thing. Always glad to read your input, thanks for posting so much valuable info.
     
  5. goatchop41

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    Posted 13/7/19
  6. Schikitar

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    Posted 13/7/19
    Where do you guys stand on using potassium or sodium metabisulfite when racking beer into the keg? My impression is that it can perhaps reduce levels of any O2 left in the keg/beer upon transfer? I tried to find some more info on that lowoxygenbrewing.com website but there's too much science talk going on for my small brain and I won't pretend to understand it..
     
  7. MHB

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    Posted 13/7/19
    Schiktar, good thought, we had a NEIPA at work that went to shit a lot faster than I was happy with so have been giving this a heap of thought.
    Still working through the numbers but will post soon with what I hope will be a simple process to get virtually no O2 in packaging. This process is designed for commercial sized systems but I'll make a Corney keg sized version.
    Oxygen is clearly a real "now" issue.
    Mark
     
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  8. f00b4r

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    Posted 13/7/19
    The link you posted Mark is going to a bitter recipe request, copy and paste error?
     
  9. goatchop41

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    Posted 13/7/19
    On my completely unscientific, unblinded experiment of n=1, I recently gave it a go. I had read about it and felt lazy when racking an IPA from fermenter to keg, so I chucked half of a crushed campden tablet in to the keg with my gelatin, purged it once with CO2, then racked from the fermenter.
    Almost two months later and it's still tasting and smelling like the day that I racked it, and the colour hasn't changed one bit. I've had issues with a couple of NEIPAs oxidising quickly in the past, so I'm definitely going to try it when transferring the next one that I make
     
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  10. brewermp

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    Posted 13/7/19
    Circling back now. The shake of the keg did improve the taste but not to original.

    I have increased the temp to 10c with +/- 2c. Whilst the taste has improved it is not like it was. I think I am going to put this down to force carbing.
     
  11. peteru

    Here, taste this!

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    Posted 13/7/19
    I've been using sodium metabisuplhite for purging. My method is fairly simple:
    • Clean keg.
    • Drain keg well.
    • Add about 100ml of correctly diluted StarSan style sanitiser.
    • Seal keg and invert / rotate for a few minutes.
    • Drain keg well.
    • Fill keg about 50% with filtered water.
    • Add 1/4 teaspoon of sodium metabisulphite and gently agitate to dissolve it.
    • Completely fill keg with filtered water.
    • Let keg stand around while I get everything else sanitised and ready for transfer from kegmenter.
    • Just prior to transfer, I use CO2 cylinder to expel all the water from receiving keg into a spare keg.
    • This purge goes through the same connector that will be connected to the kegmenter and used to transfer beer. This ensures that the interconnect is also purged.
    • Do a pressure transfer: CO2 cylinder (pressure P+10kPa) --> kegmenter (pressure P) --> recipient keg --> spunding valve (pressure P-10kPa)
    My fermentation process has been to keep the airlock (no head pressure) on the kegmenter until the krausen starts to subside (about 2-3 days for ales), then seal the kegmenter and set the spunding valve to about 150-160kPa. That should be giving me around 2.3 volumes carbonation at the 18C fermentation temps. Let it ferment out completely, then cold crash to 2C and hold it there for about 2 days before transfer. Obviously the kegmenter pressure drops at that stage, but it stays pressurised.

    I've been using a floating pickup tube for kegmenter transfers. I'm now contemplating also installing a floating pickup tube into the serving keg and doing the pressurised transfers without could crashing and with about one or two points before expected FG. Stick a spunding valve on the serving keg and let it sit next to the kegerator for a week before putting it in the kegerator. I run the kegerator at around 8C.
     
  12. MHB

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    Posted 13/7/19
    NO no no...I was just saying that the link you posted was a great read and that Schikitar (which I C&P'd) should read it.
    Shouldn't and copy peoples name without realising it formes a random link automatically
    Sorry for confusion (mine)
    Mark
     
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  13. goatchop41

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    Posted 14/7/19
    This seems extremely excessive, especially when you can just fill the keg with sanitiser at step three and skip all of the middle bit. Any reason for having such a convoluted process?
     
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  14. peteru

    Here, taste this!

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    Posted 14/7/19
    You haven't been paying attention, have you? ;)

    The sodium metabisulphite is there to lower the dissolved O2, thus avoiding the problem that the original poster raised. It's been mentioned only a few posts up, but my approach is different (less severe.)

    I would not dump large amounts of sodium metabisulphite straight into the beer - no need when I have a closed system.
     
  15. goatchop41

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    Posted 14/7/19
    Seems a bit rude to suggest that, as I have mentioned above that I have tried using SMB myself, and that you're proposing a completely different mechanism of action/use.

    How do you propose that this is doing anything more than just filling the keg with sanitiser and then pushing it from the keg with CO2 would in terms of reducing O2 in the beer? Isn't the whole point of adding SMB to add it to the beer in order to limit the dissolved O2 in the beer? Therefore adding it to water and then expelling the water would seem pointless, as there would only be a tiny bit of it left in the keg (and diluted, at that) and that would have a negligible effect.
     
  16. Schikitar

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    Posted 15/7/19
    Yeah, that's my understanding too, it's not to remove O2 from the keg but rather dissolved O2 from within the beer.. :/
     
  17. MHB

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    Posted 15/7/19
    Actually very different issues. Oxygen pickup during brewing does harm (HSA is real) but Oxygen pickup during packaging is very different.
    Oxygen picked up on the hot side is mostly pretty well bound up in relatively stable (if Oxidised) compounds.
    Dissolved Oxygen in packaging can act like a free radical and just goes around smashing up flavour compounds, then moving on to demolish another and another...

    I'm not really a fan of adding Sulfites to beer, if I were brewing super hoppy beers I would consider adding a little (~10ppm) on top of all the other steps to avoid HSA (LoDO Brewing) and take extreme measures to eliminate any O2 pickup during packaging.
    Mark

    PS - Way too much information - Sulfites in beer: reviewing regulation, analysis and role
    M
     
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  18. peteru

    Here, taste this!

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    Posted 15/7/19
    Sorry, wasn't trying to be rude, hence the wink emoji.

    Yes, it is a different approach. I don't want to add the sodium metabisulphite to my beer in any appreciable quantity.

    I want the sodium metabisulphite to scrub out the dissolved O2 from the purge water. I am also hoping it will scavenge the O2 that is present as an impurity in the CO2 from the cylinder. The beer coming from the fermenter is as oxygen free as it's going to get. I am trying to avoid introducing further O2 during packaging. Given my process, which I described, the main sources of O2 would be the gas in the receiving vessel, any liquid remaining in the receiving vessel and the gas used to expel the beer from the kegmenter. The sodium metabisulphite added to the receiving vessel will neutralise the O2 remaining in the purge liquid and hopefully also the O2 contamination present in food grade CO2 cylinders. That still leaves the O2 impurities in the cylinder CO2 that is used to provide head pressure for the transfer from the kegmenter. At this stage I don't have an answer for that, however I am hoping that the relatively short time and low pressure differential will result in minimal dissolved O2 contribution from that part of the process.

    It does not take much dissolved O2 to take off the shine. I'm trying to avoid it as much as I can. It's also one of the reasons why I don't force carbonate and only use just enough cylinder CO2 to provide sufficient pressure to get a pour. I'm even willing to accept a decrease in carbonation over the lifetime of a keg, over having it oxidise.
     
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  19. MHB

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    Posted 15/7/19
    Pretty much where I'm up to, the O2 in the bottled gas is the catch point right now.
    Getting the O2 out of the keg you are going to fill isn't all that hard.
    Come up with a couple of options: -
    1/ Fill the keg with Boiling water (DO is practically zero) has the potential to be a bit hazardous, then blow out the keg with bottle CO2. Bare minimum will reduce DO dramatically, just remember boiling water is dangerous and starts to take-up O2 as it cools.
    2/ Fill the keg with an O2 scrubbing solution. Unfortunately Sodium Metabisulphite (SMB) in water isn't all that good a scrubber at ambient. It works a lot better hot and at higher pH. Looking at a scrubbing solution made up of SMB and Sodium Carbonate. At 0.1M a Sodium Carbonate solution will be about 11pH, add in enough SMB, heat to about 60oC and fill the keg, leave for 10 minutes or so and blow out.
    Heating the scrubbing solution makes it work a lot faster and more aggressively, at 60oC it also lowers the DO in the water by about 2/3 so the scrubbing chemicals have less work to do, also a lot safer than pumping boiling water around.
    Pressurise keg to about 100kPa, turn the keg upside down and wait 10 minutes or so, ease the PRV (lowest point in keg) to expel any residual scrubbing solution.

    Thinking about it, I wonder if putting a spare keg in the gas line from the bottle to the fridge 3/4 fill with scrubbing solution (fit an air-stone to the dip tube) might cleanup any residual O2 in the bottled CO2.
    Mark
     
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  20. peteru

    Here, taste this!

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    Posted 16/7/19
    I like that idea. It also gives you an option to use a different scrubbing chemical to prevent transferring gaseous SO2. Maybe ascorbic acid would be a good choice. It would also neutralise chlorine, so you could potentially just use tap water in the O2 scrubbing keg. :)
     

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