Author Topic: Stalling Fermentation  (Read 622 times)

Offline jkniss7

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Stalling Fermentation
« on: February 02, 2015, 04:07:58 PM »
The last 5 or 6 beers that I have brewed have all seemed to stall out around 1.020 - 1.018, when I am expecting them to get down to the 1.010 - 1.012 range.  I have been pitching with White Labs California yeast, that I get going in a 1600 ML starter made with 1.040 pale malt extract wort usually two days before pitching. Though my stout made with Irish Yeast has had the same problem.

My ambient temps are around 66 degrees, and the stick on temp strips read between the 68 - 70 marks.  I have let them sit for up to two weeks with no change in gravity, and I have tried re-pitching with a fresh Cali yeast starter with no luck.  I have a high gravity DIPA that started at 1.100 and has only gotten down to 1.028... with this one I did a third pitching of Champagne yeast, and still didn't get any extra fermentation.

As for other information, these are all grain beers and I am airating with a filtered aquarium stone, for about 1 hour before pitching... The temp of my wort at pitch has typically been 67 - 68 degrees.

So I am trying to figure out, should I pitch at cooler temps, or ferment at warmer temps...  this is really getting frustrating.  Any advice would be appreciated. 

Offline homoeccentricus

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Re: Stalling Fermentation
« Reply #1 on: February 02, 2015, 04:27:02 PM »
The last 5 or 6 beers that I have brewed have all seemed to stall out around 1.020 - 1.018, when I am expecting them to get down to the 1.010 - 1.012 range.  I have been pitching with White Labs California yeast, that I get going in a 1600 ML starter made with 1.040 pale malt extract wort usually two days before pitching. Though my stout made with Irish Yeast has had the same problem.

My ambient temps are around 66 degrees, and the stick on temp strips read between the 68 - 70 marks.  I have let them sit for up to two weeks with no change in gravity, and I have tried re-pitching with a fresh Cali yeast starter with no luck.  I have a high gravity DIPA that started at 1.100 and has only gotten down to 1.028... with this one I did a third pitching of Champagne yeast, and still didn't get any extra fermentation.

As for other information, these are all grain beers and I am airating with a filtered aquarium stone, for about 1 hour before pitching... The temp of my wort at pitch has typically been 67 - 68 degrees.

So I am trying to figure out, should I pitch at cooler temps, or ferment at warmer temps...  this is really getting frustrating.  Any advice would be appreciated.

I'm a relative newbie myself, so these are just my 2 cents: you say you tried to brew  a 1.100 DIPA, and you are "expecting them to get down to the 1.010 - 1.012 range." Where does this expectation come from? Are you using brewing software? It might help if you published the complete recipe here...
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Offline Jimmy K

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Re: Stalling Fermentation
« Reply #2 on: February 02, 2015, 04:32:58 PM »
What is the recipe? It sounds like your yeast habits are good and you're getting consistent results batch to batch - so my gut feeling is that you'll need to make your recipe more fermentable. 1.100 to 1.028 is 73% attenuation. That sounds fairly good for a high OG beer and I'd bet the yeast is not stuck, it's just finished. Your grain bill might confirm that.
 
You can mash lower, reduce less fermentable grains like crystal, and/or replace malt with simple sugars to increase fermentability.
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Offline HoosierBrew

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Re: Stalling Fermentation
« Reply #3 on: February 02, 2015, 04:36:34 PM »
  +1. You should post a recipe - it helps to see the grist.  Also, what temps do you typically mash at ?  And do you use a calibrated thermometer?  Thermometers vary widely in their accuracy. You could easily be using a thermometer to measure mash temp that's off by 5-10 degrees F.  Also, do you control pH ?
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Offline dmtaylor

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Re: Stalling Fermentation
« Reply #4 on: February 02, 2015, 04:36:50 PM »
1.100 to 1.028 is 72% apparent attenuation, which is pretty darn good for such a big beer.

As for the others... it could be very dependent on the yeast strain selected.  In my experience, US-05 gives almost the same results as WLP001 but attenuates closer to 80% instead of just mid 70s.  English and Irish yeasts (like for your Irish stout) are known to be poor attenuators in most cases although there are a couple of exceptions.

It could also be extract.  Are you an extract brewer?  Try changing the brand of the extract used.  Also consider substituting some of your extract for simple table sugar.  Ultimately you will want to consider mini-mashing to use enzymes to make more of your sugars fermentable.  Personally I extract brewed for about 3 years when I started out about 15 years ago, and I could never ever get my final gravity below about 1.018.  These days with higher quality extracts it is easier to achieve but there are still some old school extract manufacturers where it will always stall around 1.018-1.020.  So if that's the case, change brands, or step up to mini-mash brewing where you have way more control over how fermentable your malt sugars are by mashing low and slow 148 F for 90 minutes or whatever.

I'll also leave you with this:

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Offline reverseapachemaster

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Re: Stalling Fermentation
« Reply #5 on: February 02, 2015, 06:04:43 PM »
If you're getting similar results with multiple yeast strains then the problem certainly isn't the choice of yeast. It also doesn't sound like your issues are related to your fermentation technique. You're pitching a good amount of yeast and aerating. To the extent that there is an issue with your beers, it would likely be a problem somewhere in the grain bill or mash procedures.

However, I'm not sure I understand how you reached the conclusion that the beers are supposed to hit a 1010-12 FG.
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Offline jkniss7

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Re: Stalling Fermentation
« Reply #6 on: February 02, 2015, 06:11:51 PM »
If you're getting similar results with multiple yeast strains then the problem certainly isn't the choice of yeast. It also doesn't sound like your issues are related to your fermentation technique. You're pitching a good amount of yeast and aerating. To the extent that there is an issue with your beers, it would likely be a problem somewhere in the grain bill or mash procedures.

However, I'm not sure I understand how you reached the conclusion that the beers are supposed to hit a 1010-12 FG.


I use BeerSmith for my calculations.  And I have brewed 29 times in the last year, 23 of those have come very close to what the BeerSmith calculation projected, which was 1.010 - 1.014 depending on the beer.  The DIPA I referenced was a bad example though, that one was only supposed to go to 1.020 and I hit 1.028.  What I was trying to infer was that for some reasons my last several beers are stopping about 0.010 points before they have in the past, and I am not sure why. 

I can post recipes later when I get back home, but they are all recipes I have brewed in the past with better success.

Offline Jimmy K

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Re: Stalling Fermentation
« Reply #7 on: February 02, 2015, 07:29:21 PM »
I'd check your hydrometer too with some distilled water - make sure it reads 1.000. I've heard the paper inside can shift if it gets bumped.
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Offline Wort-H.O.G.

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Re: Stalling Fermentation
« Reply #8 on: February 02, 2015, 07:38:54 PM »
my WAG not knowing everything about your recipe and process....one or more of the following ***:

1. poor yeast health or and or not enough
2. PH problem
3. not enough oxygen in wort
4. early flocculation of yeast-can be yeast strain, temps, and even calcium content.

***assuming you don't have a metric ton of unfermentables (based upon your past success with same recipe), and your mash temps are as described.
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Offline jeffy

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Re: Stalling Fermentation
« Reply #9 on: February 02, 2015, 10:34:05 PM »
Sometimes repitching the same yeast for several generations reduces the attenuation.  Was this fresh yeast or slurry from previous batches?
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