First Lager Fermentation Question: Stalled or Normal by Lager Standards?

Discussion in 'Homebrewing' started by koopa, Sep 29, 2013.

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  1. koopa

    koopa Poo-Bah (1,825) Apr 20, 2008 New Jersey
    Beer Trader

    I brewed my first lager (Baltic Porter) 9 days ago. Either it stalled due to underpitch or it's on the normal course and I'm just panicking because I'm only used to ale fermentation attenuation time frames.

    I read the write up on braukaizer which kind of describes my ferment as being normal to some degree I believe, but I'm still anxious and deciding whether or not to repitch today or tomorrow. If you have experience brewing lagers, I'd love to hear your opinion please.
    "Primary Fermentation

    Because of the slower yeast metabolism at lower fermentation temperatures, lager fermentations take longer than ale fermentations of the same wort. While ale primary fermentations are generally done after 3 - 6 days and final gravity is reached at that time, for lagers it can take 1 - 3 weeks and the final gravity may not be reached after the completed primary fermentation.

    In the classical lager brewing method, as described above, the primary fermentation is over after about 7 - 10 days, but the attenuation of the beer is not yet at the attenuation level that is desired at bottling time. Good fermentation management allows the yeast to be actively fermenting even during the lagering (cold storage) phase. This need to be kept in mind when brewers talk about the length of primary fermentation for their lagers: What was the attenuation when the beer was racked to a secondary and what was the attenuation of the beer when it was done?"

    Onto My Beer...

    It was a partigyle batch that came out as follows (btw: some boil kettle fermentable additions were made to the second runnings beer as well as a longer / harder boil to get the OG up that high):

    1540 billion pitched (10% short of what MrMalty recommended for a lager) into 57F wort and set to 53% for primary fermentation 9 days ago.

    My Fermentation observations thus far:

    Both at high krausen in less than 48 hours.

    Krausen is still thick on day 9 of the 1st runnings beer fermentation, although airlock activity is finally starting to slow. Plenty of yeast in suspension still, as observed in my hydrometer sample.

    Krausen was dissipated on the 2nd runnings beer by day 5 and airlock activity slowed to a crawl by then as well. Still some signs of moderate fermentation (bites, as I like to call them, on the surface of the wort) today on day 9. Hydro sample is much clearer than the 1st runnings beer, but visibly still a decent amount of yeast in suspension.

    I know the basics like airlock activity isn't always a sign of fermentation from my experience brewing ales of course.

    Onto the yeast used.......

    WLP 838 South German Lager

    1 vial in a 1500ml stir plate starter for 30 hours, crashed for 24 hours, decanted and then stepped up to a 4000ml stir plate starter for 30 hours.


    2 vials in a 4000ml stir plate starter for 30 hours, crashed for 24 hours, decanted and then stepped up again in a 1500ml stir plate starter for 30 hours.

    Should have been about 1540 billion cells in total, which was about 200 billion less than mrmalty called for.

    I'm also a bit worried that, due to my inexperience with lager yeast, the starters might not have completely flocculated in 24 hours prior to me decanting. My ale yeast always seems to be fully flocc'd in that time frame and I never even thought that lager yeast might take longer to crash cool due to it's acclimation to colder temperatures.


    1.095 OG
    1.052 Current SG (current apparent attenuation is 42.5%)
    1.023 Desired FG

    43 out of 72 gravity points already fermented (42.5% ap. at. thus far is 60% of the way to my desired 73.8% ap. at.)

    I plan on waiting a few more days before ramping up for a diacetyl rest. I really wanted to SG to be closer to 1.041 before I do the diacetyl rest on this beer, but I'm worried I won't be anywhere near it anytime soon.


    1.078 OG
    1.031 Current SG (current apparent attenuation is 55.5%)
    1.016 (Desired FG)

    47 out of 62 gravity points already fermented (55.5% ap. at. thus far is 76% of the way to my desired 79% ap. at.)

    I just started gradually ramping up to a diacetyl rest on the second runnings beer.
  2. JackHorzempa

    JackHorzempa Poo-Bah (3,446) Dec 15, 2005 Pennsylvania
    Premium Member

    I have brewed many batches of lager beers (over 50 batches) but they have all been moderate gravity beers (Pilsners, Marzens, Vienna lagers, etc.). It has been my consistent experience that after 10-14 days that the primary fermentation would be complete and my gravity readings would be only a few (2-3) points from the achieved final gravity. So, after 10-14 days my specific gravity reading might be something like 1.014 and the achieved final gravity would be something like 1.012.

    It is my guess that your beers at day 9 are nowhere near having the primary fermentation be complete. I would guess that if you let your primary continue for another week or so you will approach your final gravity reading.

    Hopefully somebody who brews higher gravity lagers will be able to share their experiences with their beers.


    P.S. I have never conducted a diacetyl rest in any of my lager beers (and I have never experienced a diacetyl problem with any of those beers) so I have no input on that topic.
    koopa likes this.
  3. hopfenunmaltz

    hopfenunmaltz Meyvn (1,346) Jun 8, 2005 Michigan

    Did you give the yeast O2 by aerating the wort (better yet a blast of O2) before pitching?

    You only under pitched a little. Let the yeast work for longer.

    Taste the beer and see if it has diacetyl. Even warm a sample as that will bring the diacetyl out. If you detect it, do a D-rest. I usually wait until the beer is about 2 degrees Plato above the target FG before I warm it up.
  4. koopa

    koopa Poo-Bah (1,825) Apr 20, 2008 New Jersey
    Beer Trader

    So basically, your low to mid gravity lager fermentations run just like most ale fermentations :slight_smile:

    I agree that it most likely isn't necessary from a diacetyl production level, but I'm more doing it with the mindset of helping the yeast get the beer down to the target FG. It's a strategy I read online and it was recommended to begin the ramp up when you are 75% of the way to your desired FG. The second runnings beer just hit that mark so I began the process. The first runnings beer hasn't yet so I'm holding off for now. I just figured my SG would be about 10 points lower already on this one by now.

    See above response to Jack and thank you both for the initial replies!

    Yes I aerated with direct 02 for 120 seconds on the 1st runnings beer and 90 seconds on the 2nd runnings beer.
  5. koopa

    koopa Poo-Bah (1,825) Apr 20, 2008 New Jersey
    Beer Trader

    One other thing that comes to mind is that my thermowrap heat pads that sits in my chest freezers and are hooked up to my dual temperature controllers both recently kicked the bucket. So I've been fermenting this baltic porter with just the chest freezer to run the cooling mode only but the temperature probe is in a thermowell inside the wort.

    So ultimately, the carboys are sitting in chest freezers that only turn on when the wort temperature raises by 1 degree above target and then turns off until it lowers to 1 degree below target. At that point, ambient temperature is the only thing warming the wort back up to the target fermentation temperature. So I'm sure that is warming process is taking much longer than usual. For that reason, I decided to try and compensate a bit by setting my desired fermentation temperature on the higher end of the recommended range.
  6. JackHorzempa

    JackHorzempa Poo-Bah (3,446) Dec 15, 2005 Pennsylvania
    Premium Member

    “So basically, your low to mid gravity lager fermentations run just like most ale fermentations” There was a smiley face after this statement so maybe this is a facetious response?

    Just to be clear, my moderate gravity ales complete primary fermentation around 5-6 days. So, my lager fermentations are about double the length of my ale fermentations (for beers around OG = 1.050).

    koopa likes this.
  7. premierpro

    premierpro Aspirant (278) Mar 21, 2009 Michigan

    I under pitch all my lagers and have never had one not finish. ( Disclamer: I do pitch on to yeast cakes. )
  8. JrGtr

    JrGtr Devotee (407) Apr 13, 2006 Massachusetts

    I'm no expert in lagers, but if the airlock is still going nuts, and krausen is still high, it appears you're not done yet. Let the yeast tell you when they're done. Can't push natural processes. You'll probably want to do a diacetyl rest when you're close, but I would think that's still a ways away.
  9. koopa

    koopa Poo-Bah (1,825) Apr 20, 2008 New Jersey
    Beer Trader

    4 days later (13 days in primary altogether) and the 1st runnings beer is down another 5 points despite no more airlock activity. It's now 1.047 (50% ap. at. and 67% of the way to my desired FG) with plenty of yeast still in suspension.
  10. evantwomey

    evantwomey Initiate (0) Jan 1, 2008 North Carolina

    As long as it's still got yeast in suspension and still fermenting, there is hope. Whenever I use first-generation yeast in a lager (even with big starters), even a ~1.050 pils will usually take at least 2 weeks to finish and 3 weeks to drop clear.
  11. koopa

    koopa Poo-Bah (1,825) Apr 20, 2008 New Jersey
    Beer Trader

    Gravity is at a standstill on the 2nd runnings beer and it's quite clear so I pitched 2 packs of Saflager today.
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