Author Topic: Stuck / stalled fermentation, tried a few methods, what else can I do?  (Read 1528 times)

Offline SJWackness

  • 1st Kit
  • *
  • Posts: 6
  • Jazz isn't dead, it just smells funny.
    • View Profile
Hi chaps,

(Allow me to say first that I'm an American, but living in Ireland where I've been brewing for a few years. I  joined this forum today as it seems more active than the ones over here.)


I've an extract brew which has been stuck at 1.020 (1.058 og) for a few weeks. I've tried raising the temperature and rousing the yeast and I've also tried repitching from a yeast (dry, same strain as first pitch) starter at high krausen and it's still stuck at 1.020 (target's 1.008-10).

It's a Bulldog kit and the 4 others I've done have always ended at 1.008-1.010. Two things were different this time round than previous: 1) the first 3 days of fermentation were very active and required a blow-off tube. Loads of chocolate scented foam came out; 2) the temperature dropped for a week, from 20°C in my fermentation chamber to 16°C. The change happened before I racked to secondary so I'm thinking quite a bit of yeast floculated and were left behind. The fermenter's now been held constant at 22-23°C since repitching the yeast about 10 days ago and still no change in gravity.


So, what options do I have? Should I try another starter but use a higher attenuating yeast instead? I have 20 litres in the fermenter and would like to reach 1.010-12 at the very least.

Could a lack of aeration cause this?


Many thanks in advance!

Cheers,
John

Offline denny

  • Administrator
  • Retired with too much time on my hands
  • *****
  • Posts: 19446
  • Noti OR [1991.4, 287.6deg] AR
    • View Profile
    • Dennybrew
Re: Stuck / stalled fermentation, tried a few methods, what else can I do?
« Reply #1 on: October 22, 2014, 06:39:00 PM »
I don't think your fermentation is stuck...I think it's done.  That's why nothing you've tried has worked.  You could do a forced ferment test to confirm that.
Life begins at 60.....1.060, that is!

www.dennybrew.com

The best, sharpest, funniest, weirdest and most knowledgable minds in home brewing contribute on the AHA forum. - Alewyfe

"The whole problem with the world is that fools and fanatics are always so certain of themselves, and wiser people so full of doubts." - Bertrand Russell

Offline dmtaylor

  • Official Poobah of No Life.
  • *
  • Posts: 3256
  • Two Rivers, WI
    • View Profile
Re: Stuck / stalled fermentation, tried a few methods, what else can I do?
« Reply #2 on: October 22, 2014, 06:46:08 PM »
The causes are all pretty clear to me: You used extract, you chilled it, and you racked it.  Next time, don't cool it and don't rack it.  That will help.  And if you can do a mini-mash with a few pounds of malt, by all means, that would be a great help as well.

As for fixing this batch, not a problem... you could whip up 2-4 quarts or so of perhaps 50% extract, 50% sugar at a reasonable gravity similar to the bigger batch (1.055-ish??), pitch some fresh yeast, and when it begins fermentation then add this to the rest of your beer and let it ferment out again at relatively high temperature like the 22-23 C.  So, basically make a big yeast starter and throw it in there when fermentation begins in earnest.
Dave

The world will become a much more pleasant place to live when each and every one of us realizes that we are all idiots.

Offline Joe Sr.

  • Official Poobah of No Life.
  • *
  • Posts: 4352
  • Chicago - NORTH SIDE
    • View Profile
Re: Stuck / stalled fermentation, tried a few methods, what else can I do?
« Reply #3 on: October 22, 2014, 07:58:26 PM »
I don't think your fermentation is stuck...I think it's done.  That's why nothing you've tried has worked.  You could do a forced ferment test to confirm that.

I dunno.  If it's the same kit as the others, it should hit the same FG or close to it.  Is it the same kit?

I do agree that all extract, depending on the extract, could be done at 1.020.  Especially if it's dark extract with who knows what percentages of what in it.

Also, have to agree with Dave.  The temp drop probably stalled the yeast and it flocc'ed out and then you racked.  Throw some active yeast at it and see what happens.  Worst case is it's done.
It's all in the reflexes. - Jack Burton

Offline SJWackness

  • 1st Kit
  • *
  • Posts: 6
  • Jazz isn't dead, it just smells funny.
    • View Profile
Re: Stuck / stalled fermentation, tried a few methods, what else can I do?
« Reply #4 on: October 22, 2014, 09:41:56 PM »
@Joe Sr
Yeah, I've done 4 of these kits before and they've always been about 1.008-10. And for all of those the conditions were the same. The only thing that changed really was a cold Autumn spell in Dublin lowered the temperature of my fermenting chamber by a huge amount.

I repitched with a starter about 2 weeks ago so I'm wondering why that didn't cause a budge. It was only about a pint at 1.020 but it was very active when I pitched it. Was it just too small or was the gravity not high enough?


@dmtaylor
If I pitch such a large starter is there going to be a problem with aeration? Or will the active yeast use the available oxygen and clean up any by by-products that might be there?


Thanks a million for the replies.


Offline Joe Sr.

  • Official Poobah of No Life.
  • *
  • Posts: 4352
  • Chicago - NORTH SIDE
    • View Profile
Re: Stuck / stalled fermentation, tried a few methods, what else can I do?
« Reply #5 on: October 22, 2014, 09:57:48 PM »
Pitch as much active yeast as possible since they are going into a hostile environment.  You want them working when they hit the beer so that they do as much as they can before they crap out.

I'm not sure I follow you're concern about aeration.  Are you worried about oxygen in the starter?
It's all in the reflexes. - Jack Burton

Offline egg

  • Cellarman
  • **
  • Posts: 58
    • View Profile
Re: Stuck / stalled fermentation, tried a few methods, what else can I do?
« Reply #6 on: October 22, 2014, 10:14:58 PM »
This is a recent issue for me too, after maybe 50 brews (12 from grain, half a dozen extracts, the rest kits...) having had my first properly 'stuck brew'.  I just repitched a 1.079 quad that had stuck at 1.016.  That's 80%AA so often would not be considered stuck, but with 15% sugar and a 64C mash (sticking to our British Isles units there!) it should be lower.  No rousing or temperature raise to 24C had done the job for me.

You have more unknowns there with the extract, so a forced ferment test would be good, to see if there's any point in throwing in another starter.  I saw Dogfish do one on Brewmasters before [SPOILER ALERT] having to chuck a whole batch of their 120.  Assuming you've got 23L, a pint sounds too small to me.  My 1L active starter with 1 sachet of US-05 (rehydrated first) has bought me 2 extra points in 2 days, with a new small kraeusen on the beer.  I didn't go beyond that for fear of changing the taste too much, but it seems to be enough to have shifted things a bit, still going...

It may well be done though, and the only option I can see would be to brew a drier batch and blend it.

Offline SJWackness

  • 1st Kit
  • *
  • Posts: 6
  • Jazz isn't dead, it just smells funny.
    • View Profile
Re: Stuck / stalled fermentation, tried a few methods, what else can I do?
« Reply #7 on: October 22, 2014, 10:34:33 PM »
I'm not sure I follow you're concern about aeration.  Are you worried about oxygen in the starter?

Yeah, shouldn't there still be some oxygen left in the starter liquid? Or will the yeast have exhausted this during reproduction by the time high krausen's reached? If not, I can't guarantee my ability to put 2 litres of starter into my FV without a bit of splashing.


Offline dmtaylor

  • Official Poobah of No Life.
  • *
  • Posts: 3256
  • Two Rivers, WI
    • View Profile
Re: Stuck / stalled fermentation, tried a few methods, what else can I do?
« Reply #8 on: October 22, 2014, 10:36:07 PM »
It might just be done fermenting.  Pitching a pint of starter probably wouldn't help much.  Try like a gallon.  And make it "dry" or highly fermentable, like egg said.  This is why I said to use like 50/50 extract and simple sugar.  The simple sugar will help bring final gravity down some.

Aeration has nothing to do with this IMHO.  Don't worry about aeration one way or the other.
Dave

The world will become a much more pleasant place to live when each and every one of us realizes that we are all idiots.

Offline a10t2

  • Official Poobah of No Life.
  • *
  • Posts: 4450
  • Ask me why I don't like Chico!
    • View Profile
    • SeanTerrill.com
Re: Stuck / stalled fermentation, tried a few methods, what else can I do?
« Reply #9 on: October 22, 2014, 10:36:56 PM »
I don't think anyone else said it… Have you calibrated the hydrometer?
Sent from my Microsoft Bob

Beer is like porn. You can buy it, but it's more fun to make your own.
Refractometer Calculator | Batch Sparging Calculator | Two Mile Brewing Co.

Offline SJWackness

  • 1st Kit
  • *
  • Posts: 6
  • Jazz isn't dead, it just smells funny.
    • View Profile
Re: Stuck / stalled fermentation, tried a few methods, what else can I do?
« Reply #10 on: October 22, 2014, 10:41:32 PM »
I don't think anyone else said it… Have you calibrated the hydrometer?

Yeah, I checked and recalibrated all of my instruments a few weeks ago. That's why my fermentation chamber was able to fall to 16°C. It had been miscalibrated during a check so it was reading 20°C when it was 16°C.

Hydrometer's fine and I've been checking sample temperatures when recording gravity.

Offline SJWackness

  • 1st Kit
  • *
  • Posts: 6
  • Jazz isn't dead, it just smells funny.
    • View Profile
Re: Stuck / stalled fermentation, tried a few methods, what else can I do?
« Reply #11 on: October 22, 2014, 10:43:55 PM »
It might just be done fermenting.  Pitching a pint of starter probably wouldn't help much.  Try like a gallon.  And make it "dry" or highly fermentable, like egg said.  This is why I said to use like 50/50 extract and simple sugar.  The simple sugar will help bring final gravity down some.

Aeration has nothing to do with this IMHO.  Don't worry about aeration one way or the other.

Cheers, I'll give that a try. This is my first ever stuck fermentation after 20+ batches of kit and AG and a pitching calculator said .5l should do. I'll build up another starter and follow this advice.

Offline klickitat jim

  • I must live here
  • **********
  • Posts: 8471
    • View Profile
Re: Stuck / stalled fermentation, tried a few methods, what else can I do?
« Reply #12 on: October 23, 2014, 02:58:22 AM »
Pitch brett?

Offline dmtaylor

  • Official Poobah of No Life.
  • *
  • Posts: 3256
  • Two Rivers, WI
    • View Profile
Re: Stuck / stalled fermentation, tried a few methods, what else can I do?
« Reply #13 on: October 23, 2014, 10:18:30 AM »
Pitch brett?

Ugh... I'm going to remember this the next time I judge sours in a competition.... you can't just fix any broken beer by adding Brett.... or can you!?!?  So the question on my mind will always be, was this an intentional Brett beer, or was the brewer simply trying to fix a beer that sucked!?
Dave

The world will become a much more pleasant place to live when each and every one of us realizes that we are all idiots.

Offline klickitat jim

  • I must live here
  • **********
  • Posts: 8471
    • View Profile
Re: Stuck / stalled fermentation, tried a few methods, what else can I do?
« Reply #14 on: October 23, 2014, 12:02:32 PM »
Pitch brett?

Ugh... I'm going to remember this the next time I judge sours in a competition.... you can't just fix any broken beer by adding Brett.... or can you!?!?  So the question on my mind will always be, was this an intentional Brett beer, or was the brewer simply trying to fix a beer that sucked!?

Or... finishing a beer that wasn't done yet, and didn't know what it wanted to be.

Is this the best candy ever? Or did some fool just drop his Hershey bar in a peanut butter jar?

Gump: "maybe it's both. Maybe both is happening at the same time."