Stuck in the mud

[chokeslam512]

Greetings all, long time lurker, first time poster.

I am experiencing a stuck fermentation on my third AG beer. I went a little big on this one and I'm hoping that the sages that be can assist me.

Imperial Chocolate Stout (There are no rules right?)
6# Klages Pale
5# Brown
2# Chocolate Malt
1# Black Patent

1 oz East Kent Goldings (5.2%) @ 60 min Boil
1 oz Fuggle (4.2%) @ 60 Min boil

8 oz Malto Dextrin @ 10 Min Boil (I am only doing single infusion right now and have experienced some mouthfeel lacking in previous AG batches)

8 oz Pure cocoa powder at flame out

OG was 1.078, I know that about .004 was the MD.

I used Wyeast Thames Valley at 77% Attenuation so my TG should be 1.017 right? Well, it has been about three weeks and I have been at 1.044 for the last week. I racked it one week ago. Every time I check, there is pressure in the airlock and every time I swirl the bucket it starts bubbling like crazy again. The temperature in my house is around 67 degrees.

My temporary solution is to swirl the bucket a couple times a day to try and get some movement going. When I transferred the wort into the primary I did it through a strainer in order to aerate it but I fear that it wasn't enough and that I'm too far along now to aerate. Should I rack again? Pitch again?

In the words of The Beatles, HELP!

 

[markcurling]

I'm certainly no expert, but if I had to guess...6# pale and 8# speciality seems very high on the speciality malts, perhaps there weren't enough enzymes for conversion so you're left with a less fermentable mash? At what temperature and for how long did you mash?

Though 44 is very high...

 

[chokeslam512]

I'm certainly no expert, but if I had to guess...6# pale and 8# speciality seems very high on the speciality malts, perhaps there weren't enough enzymes for conversion so you're left with a less fermentable mash? At what temperature and for how long did you mash?

Though 44 is very high...

Oh shoot. I mashed for 60 minutes at 155. I didn't even think/know about the difference there.

 

[chokeslam512]

Okay, I re-pitched yesterday afternoon and still nothing. Am I looking at too much unfermentable sugar from the types of malt I used? I read that brown malt is accepted as a base malt. My expertise in this matter is non existent.

I suppose my only recourse is to let it sit for another week and if the gravity doesn't change, I'll bottle it and tuck it away in the bomb shelter.

 

[pennisim]

Try brewing another quick extract beer (low OG) with your original yeast, then after fermentation is complete rack you stuck beer on the yeast cake from the new beer.
Best of luck,
Matt

 

[chokeslam512]

Will that get me any more activity then a fresh Wyeast Activator?

 

[maltbarleyhops]

you blew out with the flavouring grain. plain and simple.

but, racking over and putting away for long storage may be a healer...looooooooooooong storage.

i did the same with a Dunkelweiss, but a year and a half later its still not worth drinking.

mine was that i had some grain incorrectly labeled

 

[Ravenshead]

I'm afraid Markcurling may be right. I just bottled an RIS that had an OG of 1088. It's as black as night and tastes like unsweetened chocolate. 82% of the malt bill is plain old 2-row. Less than a pound each of chocolate malt, black patent, and roasted barley give it all the color and flavor I could ask for.

That being said, I'd still try the yeast cake trick. If that doesn't work, there's always the bomb shelter.

If it survives that, it should be drinkable. Maybe even great, who knows.

 

[BobBailey]

+1 on not enough enzymes to do the job. Not that it would make a bunch of difference in this case, but did you do an appropriate starter?

Bob

 

[winnph]

They don't cite their source, but this chart of diastatic power of malts shows that brown malt has zero DP:

http://www.brew-dudes.com/diastatic-power/630

If that's true, then the above posts are correct, and there were almost certainly not enough enzymes to convert all the starches.

 

[Ravenshead]

Assuming the brown, Choc and black malts have zero fermentables, only about 43% of your 1078 OG is fermentable. Also assuming my math skills are good this morning and I'm doing this right, with 77% attenuation you should get to 1052 as your final gravity.

43% of 78 is 33 pts of fermentable sugar
77% of 33 is 26 pts fermented
1078-1026=1052

I'm afraid 1044 is about as good as you're going to get.

 

[chokeslam512]

Assuming the brown, Choc and black malts have zero fermentables, only about 43% of your 1078 OG is fermentable. Also assuming my math skills are good this morning and I'm doing this right, with 77% attenuation you should get to 1052 as your final gravity.

43% of 78 is 33 pts of fermentable sugar
77% of 33 is 26 pts fermented
1078-1026=1052

I'm afraid 1044 is about as good as you're going to get.

Thanks guys. I really appreciate all of the advice. My big concern was with bottle bombs if I didn't have my calculations or knowledge in check. Since that won't be an issue, it's off to the bomb shelter for them. Failures, some times as valuable as successes, are not nearly as delicious.

 

[chokeslam512]

Retracted....

 

[winnph]

Assuming the brown, Choc and black malts have zero fermentables, only about 43% of your 1078 OG is fermentable. Also assuming my math skills are good this morning and I'm doing this right, with 77% attenuation you should get to 1052 as your final gravity.

43% of 78 is 33 pts of fermentable sugar
77% of 33 is 26 pts fermented
1078-1026=1052

I'm afraid 1044 is about as good as you're going to get.

I don't think it works quite that straightforwardly, since the portion with diastatic power should have enough enzymes to convert some of the starches in the other grain, but just not that much additional grain. In other words, when you add specialty malts to a mash with mostly base malt, those specialty malts are being converted, even though they don't have any diastatic power, up to the limits of the DP of the base malt. I vaguely remember finding a calculator somewhere that shows how much DP you need to convert a set amount of unmodified grain, but I seem to have lost the link.

But the gist of what you're saying is correct -- a significant portion of the starches were poorly or not at all converted, so there may be significant "sugars" or soluble starches that have not been converted.

There may be some way to fix this problem, perhaps by adding beano tablets or something?

 

[COLObrewer]

If you have a lot of time and patience you could do this: https://www.homebrewtalk.com/f127/13-gallons-unintentionally-wild-brown-can-i-use-133003/

I had the same situation a couple years ago with an FG of 1.040, I fiddled with it until I got it infected, I anticipate it being my best brew to date.

 

[Ravenshead]

I don't think it works quite that straightforwardly, since the portion with diastatic power should have enough enzymes to convert some of the starches in the other grain, but just not that much additional grain. In other words, when you add specialty malts to a mash with mostly base malt, those specialty malts are being converted, even though they don't have any diastatic power, up to the limits of the DP of the base malt. I vaguely remember finding a calculator somewhere that shows how much DP you need to convert a set amount of unmodified grain, but I seem to have lost the link.

But the gist of what you're saying is correct -- a significant portion of the starches were poorly or not at all converted, so there may be significant "sugars" or soluble starches that have not been converted.

There may be some way to fix this problem, perhaps by adding beano tablets or something?

Thanks, I was wondering if my theory was correct. That's why I added the "and I'm doing this right" caveat to my post. That does explain how he got as low as he did though.