Author Topic: Fermentation/airlock activity question  (Read 5779 times)

Offline JCarter00

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Fermentation/airlock activity question
« on: October 19, 2016, 08:19:51 AM »
Hey Folks,

Seeking some input on a situation that is perplexing me regarding an ale I have in the primary fermenter.  There is no airlock activity, but I can see the beer through the clear carboy and it looks a lot like this: https://www.youtube.com/watch?v=z7CyR1kVClE

I brewed & pitched on Friday 10/14, with an OG of 1.055.  Took a reading on Monday 10/17 and it was at about 1.030.  There was airlock activity approx 18 hours after pitching but I'd say by the morning of 10/16 it had stopped.  I was thinking stuck fermentation so when I took the reading on Monday I shook the carboy gently and the airlock started bubbling again, but next time I checked it it had stopped so I don't know how long it was actively bubbling; there was and still is a nice kreusen on top. 

So basically my point of confusion is the apparent disparity between what appears to be active fermentation happening inside the carboy and the lack of airlock activity.  The obvious answer would be lack of a tight seal, but I don't think that's the case (I'm using a plastic Big Mouth Bubbler carboy from NB with screw-top lid), since there have been periods of airlock activity.  Any thoughts here?  Am I missing something obvious?  Is it simply a stuck fermentation and the "swirling" activity inside the vessel isn't necessarily indicative of active fermentation still happening?  I'll take a hydrometer reading this evening to see what progress has been made since 2 days ago. 

Thanks!

Offline Oginme

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Re: Fermentation/airlock activity question
« Reply #1 on: October 19, 2016, 09:42:15 AM »
Airlock activity is associated with the most active phase of fermentation.  Generally once you pitch your yeast, there will be a lag phase where the yeast is assimilating to its new environment and starting to grow and multiply.  Next is the active fermentation where the yeast is going wild chomping on sugars and excreting all sorts of good and not so good byproducts.  What you seem to be in now is the clean-up phase where the bulk of the sugars have been consumed and the yeast is busy at work scavenging up many of the by-products they produced.  During this last phase, the airlock activity may be very low to almost non-existent. 

Unless it is a low gravity beer (OG less than 1.036), I expect that the total time in a fermentor should take a minimum of 10 days.  Depending upon the variety of yeast used, there will be a 4 to 20 hour lag phase, 2 to 4 days of active fermentation, and the rest being the clean-up phase.  I allow by standard gravity brews to ferment for 13 to 15 days, higher gravity brews take longer.  Following that, I cold crash by lowering the temperature slowly over a few days then allowing the carboy to sit for 3 to 4 days at 40F to 45F to allow the bulk of the yeast to settle out.

For the most part, patience is almost always rewarded.
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Offline JCarter00

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Re: Fermentation/airlock activity question
« Reply #2 on: October 20, 2016, 11:00:39 AM »
Thanks for the response.  Yes, you're right, patience is rewarded and I often need to recite CP's mantra ("Relax, don't worry.."); the carboy activity has started to mellow out which would be consistent with your statement regarding transition to clean-up phase.  Still, I'm perplexed by the lack of airlock activity after about 2 days post-pitch.  Can't help but wonder if CO2 is escaping somewhere, somehow.  I'll wait until tomorrow to do a reading and will hope it's near TG. 

Offline ihikeut

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Re: Fermentation/airlock activity question
« Reply #3 on: October 20, 2016, 06:48:50 PM »
I would suspect you had a seal problem. The air lock activity would of slowed but not quit. If it happens again I wold spray a little Starsan on all seals and see if you have a seal problem.7

Offline vince62

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Re: Fermentation/airlock activity question
« Reply #4 on: October 22, 2016, 07:07:31 PM »
I have tried two batches of sugar shine mash and no activity with yeast.  I made a starter separate at the same temp as my wort  (around 100 deg.) and added it to my wort.  It had a good amount of gas being created but there was no activity on top of the batch.  My average temp where I am fermenting is around 75 degrees so it cooled down to that and has been there for about 5 days now.  There is a lot of condensation on lid of fermenter and I haven't seen any gas venting in a couple of days.  Do I just need to start again.  This is second 20 gal. batch I am going to have to throw away.  What am I doing wrong?KTMTER

Offline nzjase

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Re: Fermentation/airlock activity question
« Reply #5 on: October 24, 2016, 01:59:12 AM »
I have tried two batches of sugar shine mash and no activity with yeast.  I made a starter separate at the same temp as my wort  (around 100 deg.) and added it to my wort.  It had a good amount of gas being created but there was no activity on top of the batch.  My average temp where I am fermenting is around 75 degrees so it cooled down to that and has been there for about 5 days now.  There is a lot of condensation on lid of fermenter and I haven't seen any gas venting in a couple of days.  Do I just need to start again.  This is second 20 gal. batch I am going to have to throw away.  What am I doing wrong?KTMTER

I am very new to all grain, only done half a dozen batches so take my opinion with a grain of salt, but why do you need to throw it away? If it hasn't been contaminated couldn't you just repitch the yeast and check the seal is tight / secure?

Offline ihikeut

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Re: Fermentation/airlock activity question
« Reply #6 on: October 24, 2016, 06:41:49 AM »
If your gravity readings are lowering your beer is fermenting. Give it two weeks if it's ale longer for lagers at temputure that is recommended for the type yeast your using. See if the reading stay the same on three samples taking over a three day period. This will tell if the yeast is done fermenting. Should not have to toss the batch, it's most likely a bad seal or airlock.
 

Offline ihikeut

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Re: Fermentation/airlock activity question
« Reply #7 on: October 24, 2016, 07:03:08 AM »
If your not seeing the gravity lower then most likely something damaged the pitched yeast.


Offline JCarter00

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Re: Fermentation/airlock activity question
« Reply #8 on: October 25, 2016, 09:54:22 AM »
I would suspect you had a seal problem. The air lock activity would of slowed but not quit. If it happens again I wold spray a little Starsan on all seals and see if you have a seal problem.7

That must have been the case; it's down to about 1.012 so it's good to go.  I noticed a very small crack in the airlock.  Not enough for any liquid to leak out of but perhaps enough for air to escape...

Offline Madbeetrootfarmer

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Re: Fermentation/airlock activity question
« Reply #9 on: October 26, 2016, 11:18:35 AM »
Hey mate.  Saw a lot of responses here for you and seems to be in line with what I have seen over the years.  Also I have had leaking around the rubber where the airlock goes into the lid.  I make it a habit of ALWAYS smelling my brew before I syphon it out into a cube or keg.  This is to make sure I have a nice sweet smell of CO2.  That way, it's a good indication that the brew firstly has fermented, and secondly that there is unlikely to be contamination from wild yeasts etc.  You will know if you have these odours.

Best Regards,
MBF.

 

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