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Fermenting Under Pressure

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

 

  1. wynnum1

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    Posted 21/1/18
    How do they make dry ice would think that would be one use for co2 .
     
  2. wide eyed and legless

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    Posted 21/1/18
    Pretty sure I put a link in where the NASA technician who is also a home brewer made dry ice from CO2 it is what they will be doing on Mars for water I believe. There is also a test plant for making petrol from CO2, but the costs outweighed the returns.
     
  3. wide eyed and legless

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    Posted 22/1/18
  4. Shadime

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    Posted 30/1/18
    Im currently doing my first pressure ferment which is a 14 litre Lager fermented with Saflager W-34/70 .(picture attached).

    I have the fermenting corny attached to a corny that im going to have as the serving keg and that has the spunding valve attached.

    It has been fermenting for 7 days and has reduced from OG 1044 to SG 1014.
    Temp was 15C until pressure reached 15psi and then temp was increased to 18C.
    I had my first taste and I can taste and smell the yeast which has a slight banana smell and taste.

    Couple of questions.
    Being pressure fermented I would have thought it would have suppressed the esters?
    Would the esters have been produced due to too much early fermentation happening before having both cornies pressurised to 15psi?

    As im going to be transfering to the 2nd corny, which is filled with the CO2 produced by the yeast, will I get this smell with every beer I pour?

    On a side note the flavour from the yeast compliments the beer.

    Thanks for any feedback.

    Cheers
    Shadime
     

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  5. wide eyed and legless

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    Posted 30/1/18
    It only happens on the Saccharomyces cerevisiae not so much on lager yeast, if you kept the 2nd corny flushing throughout the fermentation you should't get the smell of the CO2. A lot of the sulphur compounds should have been driven off .
     
  6. Dan Pratt

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    Posted 30/1/18
    ^ How much yeast did you pitch?
     
  7. Shadime

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    Posted 30/1/18
    I rehydrated the whole packet
     
  8. mxd

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    Posted 1/2/18
    for me, with 34/70 I ferment at 10 to 12, and I ignore it for a couple of weeks before I do a d-rest.

    I've never had the banana from this yeast only the popcorn :(

    Leave it alone and it should turn all good
     
    Shadime likes this.
  9. Dan Pratt

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    Posted 1/2/18
    1 packet for a lager, is not enough. I typically would use that yeast W34/70 for a keg filler beer fermented at 15c using about 6g per L dry hopping to compete with the esters it throws off. Then use that yeast cake to make my lagers/helles or pilsners always targetting about 800 billion yeast cells for a nice cold 9c fermentation.

    To suppress the esters for a lager yeast its been said that > 25psi is the pressure required to achieve that outcome.

    Id suggest you now LAGER the beer you have made in the keg in the fridge for 30days and try it again, then if its still high on esters make a decision on the beer.
     
  10. slcmorro

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    Posted 2/2/18
    Disagree 110%. I've done several at 15psi and they've turned out great.
     
  11. Haciluku

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    Posted 2/2/18
    +1

    You can listen to Beersmith #163 - Pressure fermentation with Chris White and John Blichmann. They had done several experiment with different pressure on lager, ideal pressure is 15psi.
     
  12. slcmorro

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    Posted 2/2/18
    Not entirely sure about that either. Mr Malty says for a 14L batch of 1.044 beer as per the OPs statement, 1.1 packs of 11.5gm of dry yeast is required.
    Sure, more yeast is definitely better in most cases but considering he fermented at 15c I'd hazard a guess that the cell count made up for that .1 rather quickly.
     
  13. wide eyed and legless

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    Posted 2/2/18
    But a more idealer pressure is no pressure at all, the judges could tell the difference along with Chris White that a Lager is a Lager, but in saying that I will be making a Faux Lager at 15 psi, and I know I will tell the difference but it could be nice.:)
     
  14. Dan Pratt

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    Posted 2/2/18
    Ok guys. Old mate has described a beer that has faults. I should of been more clear with response by way of suggesting to try increasing the pressure and increasing the yeast count.
     
  15. Shadime

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    Posted 2/2/18
    This is what i used to determine the pressure.
    Thanks all for your ideas, will try 2 packets yeast next time.
    Will report back once it is transferred and chilled.

    One other thing that I thought of is that the spunding valve i used was a PITA and the pressure fluctuated between 10-20 PSI so that may have played a part.

    Cheers
    Shadime
     
  16. wide eyed and legless

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    Posted 2/2/18
    Here is another podcast you may find useful.
     
  17. Maheel

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    Posted 3/2/18
    crazy thought coming...

    if you pressure ferment PFK and daisy chain to a full corny as a empty co2 / blow off and capture the c02.

    Then when you push the beer out of the PFK you...pushed water down the "out" dip tube of your blow off keg forcing the co2 out the "in" back into the PFV pushing the beer to the "drinking keg"

    saves the co2 from your tank...

    how much o2 would be in the blow off keg? i assume it mixes as it would be under pressure ?

    may be crazy????
     
  18. wide eyed and legless

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    Posted 3/2/18
    I have done this with my pressure ferment cubes, its easy to compress gas using water (mains about 70psi) my worry was the oxygen in the water mixing with the CO2 but I drank the beer within 2 weeks with no noticeable oxidisation.
     
    Last edited: 3/2/18
  19. Maheel

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    Posted 3/2/18
    interesting, i would have thought the co2 from the ferment would have a more co2 / o2 mix. but i got NFI really :)

    i probs will just continue to push it with co2 out of PVK but was something i thought about while reading the new parts of the thread
     
  20. wide eyed and legless

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    Posted 3/2/18
    Considering the yeast may take up the oxygen there should be no O2 coming out look I think it is a good idea but really needs someone more qualified to validate the idea.
     
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