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Fermenting Under Pressure

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

 

  1. wide eyed and legless

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    Posted 10/12/17
    Pressure to high?
     
  2. cliffo

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    Posted 10/12/17
    Black disconnect?
     
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  3. mtb

    Beer Bod

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    Posted 10/12/17
    No temp control
     
  4. Midnight Brew

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    Posted 10/12/17
    White Teflon tape..... relax it works, I’d be putting that gauge on the gas not the beer.
     
  5. Maheel

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    Posted 10/12/17
    no toes / safety thongs / dressing gown in the pic ?
     
  6. Maheel

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    Posted 10/12/17
    i just picked up 2 X 23L myttons / Schweppes kegs $50 each to increase my head space for some more pressure kegmenter options :group:

    # the lifesaver / post seals on the posts were stuffed but CO2 regulator -> gas bottle seals fit !!
    it let me get them cleaned out and pressure tested :p
     
  7. malt junkie

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    Posted 10/12/17
    Several places to get kits for these kegs, and prolly best to go right through the things if your fermenting in them.
     
  8. Maheel

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    Posted 10/12/17
    agreed and have ordered the right seals
    i had everything else except the LS post seals and wanted to pressure test for holes
    random searching the shed found a temp fitting seal
     
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  9. Hpal

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    Posted 10/12/17
    I've recently brewed this as well, its an amazing beer. Pressure fermented and i put the dry hops in first thing and left them in because I don't like to open the fermenter and it will ferment out in maybe 4 or 5 days anyway. One of the best beers I've made, was drinking it in 8 days
     
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  10. Dave70

    Le roi est mort..

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    Posted 10/12/17
    No!

    Yes! Clearly you're paying closer attention than me when I clicked 'add to cart'.

    Sort of. The laundry is a fairly consistent 20 deg.

    Yeah, the correct part is somewhere in express post.

    No sweat, I'm wearing hi-viz undies.
     
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  11. wide eyed and legless

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    Posted 11/12/17
    Couldn't wait for my spunding valves to arrive,pitched yeast in a special bitter with just a dash of oxygen at 2 pm, 10 pm vented the secondary cube so no air left in both cubes. At 6.15 am, both tanks decidedly out of shape and gauge reading 10 psi, a flaw I did think of was the NRV for the pressure in the fermenting vessel to push gas through the NRV it has to be greater than in the secondary.o_O
    I really wanted to keep the fermentation below 5 psi but what's done is done just hope everything turns out OK, I will be waitng for my PRV's before I do my next brew. Really didn't expect such a large volume of co2 in such a short space of time.
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  12. Dave70

    Le roi est mort..

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    Posted 11/12/17
    Careful..

    [​IMG]
     
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  13. Mardoo

    Noob What Craps On A Bit

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    Posted 11/12/17
    It's astonishing how much is produced. Pressure fermenting has given me a whole other level of amazement/appreciation for yeast.
     
  14. wide eyed and legless

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    Posted 11/12/17
    I know I will be doing a lot more reading about yeast, how a minuscule single cell organism can fill up a 25 +(3) litre head space plus 7 litres of head space above the wort and take it to 10 psi is incredible. After half an hour I went back after releasing the pressure and another gush of co2 came out, have left the valve just cracked open, really hope my PRV's come today.
     
  15. markp

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    Posted 11/12/17
    Ok guys been reading through this thread and the answer to my question is probably somewhere but I must have missed it.
    Just about to do my first pressure ferment, I have a fermentasaurus and am going to do an ipa what pressure should I set the prv for and should I do the whole ferment at the same pressure ? I would like it to naturally carbonate in the process. Any help hints or tips would be much appreciated.
    Cheers in advance.
    Mark.
     
  16. rude

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    Posted 12/12/17
    Try 5 to 10 psi for the main duration then when there is a few gravity points left up it to 30 psi
    Record youre results

    If you dont get to the 30psi relax have a homebrew chill transfer & top up carb with youre co2
    Presuming you keg
     
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  17. wide eyed and legless

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    Posted 12/12/17
    Dan says in his post (number 342) 5 psi for ales in his fermentasaurus which I would go along with, I have read quite a bit about it on other sites and it seems to come in around 2 to 5 psi. I can't find any scientific evidence to back it up, as nobody seems to have done any work on ale yeast and pressure. Except to say it doesn't work on ale yeast like it does with lager yeast, where there is plenty written about temperature and pressure for lager.
     
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  18. Mardoo

    Noob What Craps On A Bit

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    Posted 12/12/17
    If you want esters from the yeast keep it below 8psi. If you want less esters, keep it above 15psi. If you’re harvesting yeast, don’t go above 30psi.

    Regarding carbing, I don’t have my results in that regard dialled in yet. At the moment I’m leaning towards setting the spunding valve a few psi above the pressure you need in order to carb to the desired carb level at fermentation temperature. Set to that point after the first three days of fermentation. I’m getting inconsistent results carbing in the fermenter and need to work out why. It’s likely I’ll ferment to the end at carbonation pressure and then immediately transfer for finishing with forced carbonation. I haven’t given up yet though ;)
     
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  19. Lyrebird_Cycles

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    Posted 12/12/17
    It is known that the major effect of pressure is due to the increase in CO2 concentration.

    As a first cut then, we could apply the known equation for [CO2] vs temperature and pressure to come up with an equivalence

    P1 = P2 . e^ (2617.25 * (1 / T2 - 1 / T1)).

    Note that P and T are absolute values in SI units, so a ferment termperature of 20 oC would be entered as 293.15 oK and a top pressure of 0 kPa would be entered as 101.3 kPa.
     
    Last edited: 12/12/17
  20. Dave70

    Le roi est mort..

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    Posted 12/12/17
    Here's a handy chart that was referenced earlier in regard to carbonation.
    http://kegking.com.au/wp/wp-content/uploads/2017/06/KEGKING-Set-Forget-CO2-Carbonation-Chart.png

    I'm actually considering running the ferment out then gassing up a PET and force injecting the appropriate amount of sugaz dissolved in a little boiled water and bulk priming if the ferment doesn't give me the bubbles I need.
    But from memory I think that will take a couple of weeks. So more likely will crack sooner, give in and force carb.

    Hopefully your spunding valve will prove more accurate than mine that seems as precise as a two bob watch, which really doesn't help when trying to predict CO2 absobsion.
     
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