First Stuck Fermentation, what do I do now?

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imperialist

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I brewed a robust porter on 12/18 and beer calculus tells me I should have a 1.015 FG by now, but its 1.024! It tastes great but I'm worried that if I bottle it now I will have two cases of bottle bombs on my hands. Over the last two weeks I've agitated it twice to get the yeast back into suspension but so far to no avail. Can you all look at my recipe and tell me if there are just too many unfermentable sugars from the crystal malt, chocolate malt and black patent. Any suggestions on how to get this FG lower would be great. Maybe a tsp of yeast energizer or something? I'm hoping I don't have to repitch but i will if I have to.
 
Silent Night Porter
Beer Style: Robust Porter
Recipe Type: Extract with Specialty Grains
Brew Date: 12/18/11

malt & fermentables
% LB OZ Malt or Fermentable ppg °L
76% 6 6 Briess CBW Golden Light LME 35 4 ~
12% 1 0 Crystal 60L 34 60 ~
6% 0 8 Chocolate Malt 34 475 ~
6% 0 8 Black (Patent) Malt 25 500 ~
Batch size: 5.0 gallons
Boil vol: 6.5 gallons

hops
use time oz variety form aa
boil 60 mins 1.0 Fuggles pellet 4.0
boil 15 mins 0.5 Simcoe leaf 11.9
boil 15 mins 0.5 Tettnang pellet 3.5
boil 1 min 0.25 Simcoe leaf 11.9
boil 1 min 0.5 Tettnang pellet 3.5


yeast
White Labs London Ale (WLP013)
ale yeast in liquid form with medium flocculation and 71% attenuation


Alcohol
5.1% ABV / 4% ABW
Calories
175 per 12 oz.

misc
use time amount ingredient
boil 15 min 1 tsp Irish Moss info
 
What was your OG?

1.024 is a bit high but I wouldn't worry about it. If I were you I'd leave it on the yeast two or three more weeks (undisturbed!) then just bottle it.
 
The OG was 1.058 which means it the yeast only chewed up .034 gravity points. Why undisturbed? I had read that by giving the fermenter a little agitation it puts the yeast back in suspension so it can dork more, do you think this is a bad idea?
 
I would pitch more yeast. Maybe your original vial was older and less viable.

Since at this point you have beer, and not unfermented wort, you would not want to oxygenate it. Swirling is more for the first few days, if the yeast hasn't kicked off yet.
 
The OG was 1.058 which means it the yeast only chewed up .034 gravity points. Why undisturbed? I had read that by giving the fermenter a little agitation it puts the yeast back in suspension so it can dork more, do you think this is a bad idea?

The only reason not to disturb it would be to let the yeast settle out before you rack it to your bottling bucket.

It's not that uncommon for extract beers to get stuck around 1.020. This one is obviously a bit higher.

As the poster above suggested, you could try pitching more yeast. If you were to do that, I'd consider making about a 1 litre starter and pitching it at high krausen (12-18 hours). But you might only get a few more gravity points lower by doing that--so you have to consider the cost and trouble versus the potential gains.

My suggestion to just leave it is based on the fact that you like the flavour of the beer and IMO are unlikely to get bottle bombs.

If you are going to continue to make extract brews, you have to really make sure you pitch enough yeast. I'm guessing you didn't use a starter--be sure to do that next time. Also make sure your wort is as well-aerated as you can get it.

Good luck!
 
Is your hydrometer zero'ed in with distilled water? If not you might already be @ 1.020. Which as previously mentioned for extract is not unusual.
 
6.6lbs extract, 2lbs of crystal, chocolate, and black malt will leave lots of unfermentables, combine that with likely underpitching yeast and you likely are at your final gravity.
Two weeks fermentation could also be short. I'd recommend you keep rousing the yeast and give it more time, and check the gravity to make sure it is stable for at least several days straight before bottling.
 
pdxal said:
6.6lbs extract, 2lbs of crystal, chocolate, and black malt will leave lots of unfermentables....

+1 - might be done...but give it another week or two to make sure.
 
I haven't dialed in the hydrometer with distilled water yet, thats a great idea. I had no idea that extract brews finish higher. Why is that exactly? Out of the twelve batches I've done so far only on other one finished above 1.014 which is why I was concerned aboout this porter. Next time I'll definitely use a starter because I think you guys are right that I have been underpitching.
 
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