Author Topic: Restarting a stuck fermentation, methods?  (Read 3100 times)

Offline jivetyrant

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Restarting a stuck fermentation, methods?
« on: October 21, 2011, 06:41:46 AM »
Hi all, it's been far too long since I've posted!

I have a problem brown ale that's stuck at 1.020, I'm shooting for 1.014.  It's not cloyingly sweet, but the sweetness that's present is masking the malty, hoppy flavor I was going for.  The recipe is as follows;

OG 1.072
FG (current) 1.019

12 oz               Caraamber
12 oz               Caramel Malt - 60L
8 oz                 Light Chocolate
2 oz                 Roasted Barley
8 lbs                Light Dry Extract
8 oz                 Brown Sugar, Dark
1.00 oz               Warrior [15.00 %] - Boil 90.0 min       
1.00 oz               Vanguard [5.50 %] - Aroma Steep 20.0 min
1.0 pkg               Dry English Ale (White Labs #WLP007) (no starter, I realize this is probably the problem)
0.50 tsp              Yeast Nutrient (Boil 10.0 mins)
0.50 tsp              Irish Moss (10 mins)

I've tried rousing the yeast and feeding it another 1/2 cup boiled brown sugar, no luck.  I've tried re-pitching a packet of US-05, no effect.  I have some spare packets of T-58 and S-33, along with some other misc dry yeasts.  I read an article a while ago about making a starter and adding some of the stuck beer every day for several days in a row to acclimate the yeast to it's environment, then adding some extra sugar and pitching during high krausen.  I've never tried this before, but it seems to make good sense.  Would pitching some re-hydrated T-58 or S-33 along with a little extra sugar be enough, or should I go the route of the acclimated starter?

Thanks!

Offline richardt

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Re: Restarting a stuck fermentation, methods?
« Reply #1 on: October 21, 2011, 06:56:26 AM »
You probably won't get much below 1.020 given that you used 8 lbs of extract--the fermentability of canned extract is fixed by the maltster not by you.

The sweetness may be due, in part, to the use of extract, as well as the 2 lbs total of Caramber, C60 and dark brown sugar 20% of the sugars in your recipe.  The sucrose component of the dark brown sugar itself tends to give a drier, thinner perception, but the dark molasses used to make dark brown sugar may increase your perception of "sweetness" based on the flavors.

Offline James Lorden

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Re: Restarting a stuck fermentation, methods?
« Reply #2 on: October 21, 2011, 06:58:17 AM »
I find that the best way to get a fermentation kicking again is to raise the temps.

If you are familiar with this recipe and the fermentability of the extract you used then you could try raising temps to 75 degrees using a basic heating pad.

It looks like you have close to 75% apparent attenuation right now which is pretty good.  You might just be done!  I'd estimate your ABV to be around 6.5% right now and at those levels I find that alcahol can add a bit of a percieved sweetness.  Also, carbonation level will affect the final flavor as the carbonic acid and bubbles will cut through some of the sweetness perception.
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Offline bluesman

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Re: Restarting a stuck fermentation, methods?
« Reply #3 on: October 21, 2011, 09:45:23 AM »
The remaining sugars may be unfermentable at this stage. The extract used could be the culprit here, as previously suggested. One option is to blend in some drier beer to help lower the gravity. In the future it might be worthwhile to do a Fast Ferment Test to better understand the fermentability of the extract used in your recipe. Then you can adjust your recipe to achieve the desired result.

http://www.braukaiser.com/wiki/index.php?title=Fast_Ferment_Test
« Last Edit: October 21, 2011, 10:01:03 AM by bluesman »
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Offline jeffy

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Re: Restarting a stuck fermentation, methods?
« Reply #4 on: October 21, 2011, 09:51:01 AM »
I will echo what richardt says in his post above.  From your recipe details I think you've got as complete a fermentation as you can expect.
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Re: Restarting a stuck fermentation, methods?
« Reply #5 on: October 21, 2011, 10:03:10 AM »
You probably won't get much below 1.020 given that you used 8 lbs of extract--the fermentability of canned extract is fixed by the maltster not by you.

The sweetness may be due, in part, to the use of extract, as well as the 2 lbs total of Caramber, C60 and dark brown sugar 20% of the sugars in your recipe.  The sucrose component of the dark brown sugar itself tends to give a drier, thinner perception, but the dark molasses used to make dark brown sugar may increase your perception of "sweetness" based on the flavors.

He used dry extract. While I agree that this may be the culprit I have managed to get extract batches to attenuate better than that. He also adds brown sugar which should lower the FG a bit overall.

**EDIT** could ne not take a small sample, say a pint, of the too sweet beer and add a whole packet of dry yeast and swirl as if making a starter to determine if there is any fermentable sugars left? sort of a post hoc FFT?
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Offline jivetyrant

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Re: Restarting a stuck fermentation, methods?
« Reply #6 on: October 23, 2011, 06:50:59 AM »
A few notes that I forgot to mention in the OP.  The dark brown sugar used was actually unprocessed mexican brown sugar, otherwise known as panella.  Also, the blowoff was so vigorous that a large amount of active yeast was blown off in some unintentional top cropping.  Thankfully I had used a sanitized 3 gallon glass carboy with some tap water in it as my blowoff catcher, so when I noticed that the initial fermentation had stalled out very high (1.30+, I can't remember the exact number) I was able to decant off most of the liquid in the 3 gallon carboy and pitch the sizable yeast cake back into the main fermenter as though it were just a monster sized starter.  That worked and didn't spoil the batch (I was genuinely worried about that) dropping the gravity to it's current level.  

I will take one more stab at dropping another few points with some highly attenuative yeast, probably S-33.  The idea of said post hoc FFT sounds like a good one, I will pull a sample large enough to take a hydrometer reading and pitch a whole packet of S-33 and see what happens!  If I have any success I will pitch a packet along with a small snack for the yeast and hit it with a heating pad up to 75ish.  Here's to hoping!

Related question; I plan to dry hop with some homegrown chinook, is there any reason to bother racking to secondary to dry hop?  It's whole leaf, so most of it will just float on top.  I find myself shying away from secondary fermentations lately, the more reading I do on the subject the less necessary it seems for ales, it just seems to add more risk of oxidation and other accidents to the mix.

Offline dmtaylor

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Re: Restarting a stuck fermentation, methods?
« Reply #7 on: October 23, 2011, 07:46:27 AM »
I agree with the others.  Extract has a lot of unfermentables and will not let the gravity budge any lower, no matter what you do, short of Beano (...and whatever you do, DON'T try Beano!  Very bad idea!  I know this from experience).

As for dry hopping, sure, you can go ahead and throw in your dry hops in the primary.  I wouldn't hesitate to do this.  Go for it.
Dave

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Re: Restarting a stuck fermentation, methods?
« Reply #8 on: October 23, 2011, 09:21:36 AM »
He used dry extract. While I agree that this may be the culprit I have managed to get extract batches to attenuate better than that. He also adds brown sugar which should lower the FG a bit overall.

I think the key here is that the recipe contains a significant amount of crystal malt (1.5 lb), plus whatever crystal malt was in the extract to begin with. The "grist" was something like 15-20% crystal malt overall.

Even if the sugar fermented out fully, 8 oz in a 5 gal batch would only drop the FG ~0.0018.
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Re: Restarting a stuck fermentation, methods?
« Reply #9 on: October 24, 2011, 07:52:20 AM »
He used dry extract. While I agree that this may be the culprit I have managed to get extract batches to attenuate better than that. He also adds brown sugar which should lower the FG a bit overall.

I think the key here is that the recipe contains a significant amount of crystal malt (1.5 lb), plus whatever crystal malt was in the extract to begin with. The "grist" was something like 15-20% crystal malt overall.

Even if the sugar fermented out fully, 8 oz in a 5 gal batch would only drop the FG ~0.0018.

yeah I though of that after I posted. Hence the FFT suggestion. Mostly was just pointing out that it was not canned extract :)
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Offline rjharper

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Re: Restarting a stuck fermentation, methods?
« Reply #10 on: October 24, 2011, 01:42:53 PM »
I agree with the others.  Extract has a lot of unfermentables and will not let the gravity budge any lower, no matter what you do, .

With respect, this is one comment I see a lot that really bothers me, and it's really nothing personal Dave, because I've had some great advice from you in the past.  I brewed extract for over 6 years before I recently switched to AG, and I could reliably ferment recipes with 6, 7 even 9lbs of LME down to 1.012 or beyond.  It perfectly possible to make well attenuated, dry beers with extract if done properly, using fresh extract.  Simply blaming extract as the cause for poor attenuation I think can be a little premature.  The OP admitted to no starter.  There's over 2lbs of crystal or chocolate malt.  There's no mention of aeration or oxygenation technique.  Fermentation temperature?  Stalled from excessive krausen blow off?

I'm not trying to start an argument here, just offering my opinion as a long term extract brewer.  There's more to it than just extract... :)

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Re: Restarting a stuck fermentation, methods?
« Reply #11 on: October 24, 2011, 01:45:22 PM »
I agree with the others.  Extract has a lot of unfermentables and will not let the gravity budge any lower, no matter what you do, .

With respect, this is one comment I see a lot that really bothers me, and it's really nothing personal Dave, because I've had some great advice from you in the past.  I brewed extract for over 6 years before I recently switched to AG, and I could reliably ferment recipes with 6, 7 even 9lbs of LME down to 1.012 or beyond.  It perfectly possible to make well attenuated, dry beers with extract if done properly, using fresh extract.  Simply blaming extract as the cause for poor attenuation I think can be a little premature.  The OP admitted to no starter.  There's over 2lbs of crystal or chocolate malt.  There's no mention of aeration or oxygenation technique.  Fermentation temperature?  Stalled from excessive krausen blow off?

I'm not trying to start an argument here, just offering my opinion as a long term extract brewer.  There's more to it than just extract... :)


Yes, it's possible, but in my experience not with every extract.  Not every extract has the same ingredients or processing methods.  Some are much more fermentable than others. 
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Offline dmtaylor

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Re: Restarting a stuck fermentation, methods?
« Reply #12 on: October 24, 2011, 02:39:18 PM »
RJ, thank you for the feedback.  My opinions are likewise based on my experience.  I too was an extract brewer for roughly 6 years, but this was back about 10 years ago.  In my experience, I could NEVER get a final gravity below 1.018.  However, I compensated for this by jacking up the OG to get the desired ABV level.  I think perhaps the extracts made back then were not as attenuative as some brands you can buy today.  And I do know for a fact that when comparing Munton's with some other brands, the differences in fermentability are huge.  John Bull, for example, makes for a super thick sweet beer, guaranteed every time, even if you add sugar.

I guess I should have said, *maybe* this is an extract issue.  It is indeed quite likely.  But I'll admit that it is equally likely to be due to other factors including underpitch, which I had not seen in the earlier posts (my mistake).

As always, just trying to help, based on the experience that I have.  And to say that my experience is the end-all, be-all would be delusional.  Nevertheless, I do like to think I'm right at least 90% of the time.  Damn near omniscient, actually.   :o  ;)  ;)  ;)
Dave

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Offline rightasrain

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Re: Restarting a stuck fermentation, methods?
« Reply #13 on: October 24, 2011, 02:49:10 PM »
This is all good to know. I have been having this problem lately. I was using extract. But I just took the jump to all grain :). I was thinking it might be the warmer weather of the summer. I don't have fermentation control yet. Could this be contributing? Or does fermentation control just help with some of the off flavors?
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Offline dmtaylor

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Re: Restarting a stuck fermentation, methods?
« Reply #14 on: October 24, 2011, 02:53:24 PM »
Yeah, temperature control is more for preventing & mitigating off-flavors.  If you're having a high final gravity issue, as the others have suggested, it could be the extract, and/or pitching rate, too much crystal malt, screwing up gravity measurements.... lots of variables.  I was wrong to jump to any conclusions because there are so many variables.
Dave

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