Fermenting under pressure

Discussion in 'Beginners Brewing Forum' started by rbixby03l, Feb 19, 2020.

  1. rbixby03l

    rbixby03l New Member

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    A quick question from a beginner.
    I am fermenting a Munich Helles under pressure, and a friend said I should move it to room temp for a few days at the end for a couple days.

    Is this true even under pressure.
    it was my understanding that with the pressure, the temperature during fermentation wasn't as important.

    OR, does it mean, whatever the temp was during fermentation (even under pressure) I need to find a slightly warmer place for a couple days?

    Do I still keep it under pressure during the rest?

    Thanks in advance!!!!

    Bob
     
  2. Trialben

    Trialben Well-Known Member

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    I still raise ferment temp at the end to help Finnish of the beer.
    Stable temperatures are still important I'd say you still don't want any major temp swings to cause the yeast to get sluggish and flock out.

    I'd bet if you can just keep it the same would suffice over moving it to a warmer location just might need an extra day or three :).
     
  3. rbixby03l

    rbixby03l New Member

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    Thank you!!!
     
  4. Meatwad

    Meatwad Member

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    Not to necro this thread but here's my experience: I ferment all of my Helles under 1 bar of pressure at 60-62F and don't raise temp and they're finished and clean in 7 days.
     
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  5. simonUK

    simonUK New Member

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    Hi Meatwad, can you tell me a bit more about your pressure fermentation? I about to use a 58L kegmenter for my first experiment in helles brew under pressure. I hope you don't mind some questions

    Do you allow pressure to build through CO2 generated by fermentation or pressurise at the start?
    What yeast are you using? I have Wyeast 2308 Munich Lager...any experience with that?
    What initial cell counts do you aim at? or batch size vs starter size?

    Cheers
    Simon
     
  6. HighVoltageMan!

    HighVoltageMan! Well-Known Member

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    I started fermenting lagers under pressure last December, but I do it at 46-48F. The first beer I did was a German Pils at 7.5 PSI (1/2 bar) and it was the cleanest lager I ever brewed. I put it in a competition in Milwaukee and got 2nd Best of Show. So I would encourage you to pursue that path, dropping temperatures will increase sulfur compounds with some yeasts which is a flavor component in German lagers. I believe the extra pressure mimics tall conical fermenters found pro breweries, the yeast is under 7-8 PSI at the bottom of a 15-20 foot high fermenter.

    Raising temperature is optional, especially if the fermentation went well. I raise temperatures, but I start at 45-46F. I haven't tried it at 62F like most people, but if I did I wouldn't raise the temperature because it's really not necessary since the beer was fermented as an ale (most likely it has no diacytel or "butter"). I let the fermentation build pressure from the start, the fermenter is on a spunding valve right away, pressure builds at 45-46F in about 18-24 hours to a pound or two and then it up to 7.5 PSI in 36 hours. My pitch rate (the amount of yeast) is fairly high to compensate for the lower pitching temperatures. If you raise the temperature to 62-64F the pitch rate can be reduced.

    The things about pressurize fermentation I noticed have been:
    1. The beers are way cleaner, especially German yeasts like WY2124 and WLP830. The colder you go, the cleaner they get (46F is the bottom end of temperature). The colder you ferment, the pressure can be reduced. The makes it a little easier on the yeast to lower the pressure, some have had some bad results above 15-20 PSI.
    2. They still produce sulfur at low temperatures, but at a reduced rate. The sulfur level is nearly perfect after fermentation at 46-48F and there is no need to try to reduce the sulfur level after fermentation. No more fart bombs.
    3. The yeast ferment a little slower for the temperature. Even when the temperature is higher the yeast take their time. I usually figure another 2-3 days, but at 62F it would still be faster than a beer fermented at 45F with no pressure.
    4. I noticed the attenuation is better, not sure if it's just me or the yeast. I have hit as high as 87% with a lager yeast. You usually only see this high of AA% with Belgian yeasts.

    So far I like fermenting under pressure. Good luck and brew on!
     
  7. simonUK

    simonUK New Member

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    Thanks HighVoltageMan
    That is comprehensive...very much appreciated.
    I am matching a recent Helles recipe brewed without pressure so it will be an interesting comparison
    Cheers!
     
  8. Meatwad

    Meatwad Member

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    I seat the keg lid with 20-25 psi of external CO2 and then back the spunding valve to 14 PSI. I use Weihenstephan lager primarily (34/70) and have also used Augustiner (Harvest, Bayern Lager). I pitch at 0.75M/ml/degree plato for 4.5 gal batches in a keg.
     
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  9. simonUK

    simonUK New Member

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    Thanks for the details....I'm looking forward to giving pressure a go
    Cheers
     

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