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Fermenting Under Pressure

Discussion in 'General Brewing Techniques' started by wobbly, 12/7/12.

 

  1. Mardoo

    Noob What Craps On A Bit

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    Posted 12/1/18
    Actually, I have two with cut dip tubes which I prefer for dry hopping, and two with uncut dip tubes which I prefer for the ferment.
     
  2. malt junkie

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    Posted 12/1/18
    Do you use the pure screens for both ferment and DH? oh and do I just slip that over the dip tube, for my kegmenters I need a way of holding the screen in place, was thinking of crimping them with pliers unless there are other suggestions?
     
  3. barls

    causer of chaos and mayhem

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    Posted 12/1/18
    they are a pretty firm fit on the kegs im using them on
     
  4. Maheel

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    Posted 12/1/18
    was going to dry hop in both PFV and maybe then in corney using tea-balls at this stage

    might see if LHB shop has them but also trim the pickup as

    is the silicone tube re-extension if needed a sound idea but ?

    cheers for input
     
  5. Digga

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    Posted 12/1/18
    I've found tea balls (supposed to be stainless) went rusty over the course of 3 months while drinking a beer they were in.

    As you can imagine the beer was anything but good and left a fair rust stain / patch on the bottom of the keg.
     
  6. squirt in the turns

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    Posted 12/1/18
    Total n00b to fermenting under pressure here - about to attempt for the first time. Apologies if this question is answered somewhere in this thread already - I haven't reviewed all 500 posts o_O

    With a PFV (in my case a 50 L keg with shortened dip tube), is it a good idea to pressurise with pure oxygen from a cylinder to oxygenate wort? It seems to me like if this was properly controlled it would be a great way to get the right amount of oxygen dissolved at the start of fermentation. It also seems likely that it would be pretty easy to get way too much oxygen in there, to the point that it's more than the yeast would need/use, or even get to toxic levels. Has anyone had success with this? If so, what pressure should the O2 be injected at, and should the wort be agitated to get more into solution? And how long for? Wort temperature I assume would have an impact too.

    I actually plan to no-chill in the 50 L keg purging and pressurising with CO2 to 300 kpa until ready to ferment, then pitch yeast, inject O2 directly, then attach spunding valve and set for 15 PSI.

    Planning to make a light lager with W-34/70. Is pure O2 overkill/unnecessary with dried yeast anyway? Is there a consensus on how warm w-34/70 can go under pressure? Looking for a faster primary as I have thirsty in-laws inbound soon.

    With the setup Denobrew's describing here (spunding valve on separate keg) how does the keg get purged? If it starts out with regular atmospheric gas in it, then it's going to end up with a mix of that original gas (albeit at a lower concentration), and CO2 from the ferment, so not exactly desirable for dispensing or whatnot. If it starts out full of water/starsan then if would get a complete purge, but I can't see how a spunding valve can be used in that situation.
     
  7. Denobrew

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    Posted 12/1/18
    With the setup Denobrew's describing here (spunding valve on separate keg) how does the keg get purged? If it starts out with regular atmospheric gas in it, then it's going to end up with a mix of that original gas (albeit at a lower concentration), and CO2 from the ferment, so not exactly desirable for dispensing or whatnot. If it starts out full of water/starsan then if would get a complete purge, but I can't see how a spunding valve can be used in that situation.[/QUOTE]







    I also transfer to the keg that has been purged/pressured from the fermetersaurus. The o2 would be negligible I imagine? The keg is purged constantly for the duration, maybe 5 days depending on brew - yeast - temp et cetera. On a home brew scale, it's certainly a long way from where I started. The closest thing to zero oxygen in the finished beer I have come up with so far. I hear you on the pushing out water proposal, but I would need to have another receiving keg of a greater volume to recieve the water. Not sure I'm ready to go to that extreme yet. Let me know if you have any other ideas to help minimise o2 further.

    Cheers.
    Edit. Not real good at this on the phone
     
  8. Jack of all biers

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    Posted 12/1/18
    Or just take out the liquid dip tube (I'm assuming there is a liquid dip tube similar to the cornies), replace it with a short gas tube and put on one of the KK floating ball dip tubes that take from the top of the beer. That way you could easily replace the liquid dip tube at a later date.
     
  9. wide eyed and legless

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    Posted 13/1/18
    Your right about the O2 it should be controlled, and do you really need it? I am new to this but have been reading up quite a bit on yeast, good article here read under Oxidative stress. (http://onlinelibrary.wiley.com/doi/10.1111/j.1574-6976.2007.00076.x/full)
    Also lots of good info on the Low Oxygen Brewing site (http://www.lowoxygenbrewing.com/) these guys seem to target 8 ppm, so not so much. As for the purging, post 449 by wynum, filling the keg with water (but better with sanitiser added) and forcing it out with bottled CO2 will purge the keg, you will not need the spunding for that, or running your venting CO2 through 2 or 3 sanitised kegs for 5 days will purge them. Worthwhile reading the links you should find them helpful.
     
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  10. Jack of all biers

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    Posted 13/1/18
    Good links WEAL. Thanks for the yeast stress one, a good one indeed.
     
  11. Maheel

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    Posted 14/1/18
    I ended up trimming 50mm of the tubes of the 23L's, got two going in the ferment fridge as i went and bought another spunding valve.
    A summit and cascade ale and an all summit ale.

    I dont yet purge my receiving kegs just run the beer out into the beer out tube of REC keg and transfer with co2, slow to begin to limit "spash" using the spunding valve on the REC keg?


    How sanitary would it be purging sanitized receiving kegs with co2 from the ferment FPV outside the ferment fridge?

    FPV in fridge -> rec keg outside fridge -> spunding on that keg.
    once FPV fermented disconnect and crash chill FPVkeg
    push beer into purged keg when ready etc
     
  12. Jack of all biers

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    Posted 14/1/18
    If it can be done on your system with everything in between sanitised then it is as sanitary as you can get it. If there is a risk of yeast blow off from the FPV, then maybe have a minikeg inbetween to collect blow off and daisy chain it to your REC keg to receive the CO2. If you want to be doubly sure (and save tank CO2) then you could daisy chain in one more step and fill the REC keg with sanitising solution and have another keg daisy chained to it to receive the sanitising solution. You just have to ensure that the last keg on the chain has a volume as big or bigger than the REC keg so that overflow is not a problem. On the same note, it may be best using phosphoric acid or H2O2 type sanitising solutions rather than a foaming one like Starsan to avoid foam being blown through your spunding valve.

    FPV in fridge -> mini keg -> REC keg full of sanitising solution -> spare keg (as big or bigger than REC keg) with spunding valve
     
  13. malt junkie

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    Posted 14/1/18
    my only issue is if the brew your spunding ends up infected then so are/is the keg/s purged this way.
     
  14. Maheel

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    Posted 14/1/18
    yeah, i even had concerns about how sanitary it all would be..

    think i will stick to just filling the REC keg and live with that bit of oxy
     
  15. Maheel

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    Posted 14/1/18
    edit double post
     
  16. droid

    somewhere on the slippery slope with a beer in han

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    Posted 14/1/18
    I'm going to get a tab welded onto the underside of my kegmenter lids, something like the tabs the newer KK 19ltr kegs have for hop socks etc...then do a pressure ferment with a bunch of hops inside in a stocking. Then transfer to another serving keg that's purged and has another hop sock in it, if it's needed..to mix up the dry-hops in each 19ltr keg a bit

    Any tips on the style of tab/attachment to put on?

    I thought I read on here that hops were toxic to yeast - how are people finding the yeast performing with hops added at the start like this?

    cheers
     
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  17. wide eyed and legless

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    Posted 14/1/18
    The spunding would be at the far end of the daisy chain, the venting gas going through the kegs and finally the spunding valve. So no chance of infection from the valve.
     
  18. Digga

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    Posted 14/1/18
    He states that if the beer your fermenting get / is infected then there will be the infection in the Daisy chained kegs and spudding valve. I would imagine the infection would carry in the CO2 produced and everything would need re-sanitation. I don't know what bacteria can travel / live in co2 though.
     
  19. wynnum1

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    Posted 14/1/18
    What filters are there to stop infection transferring.
     
  20. Jack of all biers

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    Posted 14/1/18
    This is a bit of a silly what if isn't it? I mean if your sanitation was so bad that your brew was infected it is probably mute anyway as you would likely not want to drink it (and if you did, would it matter). This is really one of those what if questions that goes no where.

    What's being said is that the gas carries the infection (being either wild yeast or bacteria)? Not really. As WEAL stated is correct. Bacteria and wild yeast hitch rides on particles (dust, blow off etc). If there is dust in your daisy chain system, then you have not cleaned or sanitised it properly. The CO2 from the hypothetical infected ferment would travel through the system and at worst you will get some of the off aroma's from the infected beer you are brewing and/or any other gases (sulphur gases etc). If there was an infection in the fermenting brew then the bacteria/wild yeast would only travel with blowoff material. This would travel through the first tube to the bottom of the mini keg and stay there. It would need to be highly pressured to mist enough for it to pass up to the top of that keg and further through the lines to the REC keg. Not impossible, but rather improbable. I go back to the what if thing.
     
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