Imperial Sweet Stout FG expectations

[Vertra]

I have a big chocolate milk stout still in primary from 2 and a half weeks ago that we have lovingly dubbed "Cowsmanaut". It is currently sitting at 1.038-1.039 FG. Should I or should I not be surprised based on this, looking back on it, insane recipe.

21 lbs maris otter
3 lbs C/C 40L
3 lbs chocolate malt
1 lbs chocolate rye
1 lbs chocolate wheat
1 lbs roasted barley
3 lbs lactose milk sugar <------ Oops?

we also pitched 16 oz brown sugar, 16 oz of pure cocoa, 12 oz of chocolate syrup, 12 oz of molasses

This was a 10 gallon batch with a 1.090 OG that we split into 2 separate fermenters with their own yeast strain. One was the Irish ale, one was the English ale. They each had a 1.5 qt oxygenated and periodically shaken starter which is admittedly underpitching for gravity. The fermentation temp was 68 F.

I tested the gravity a week ago and it was 1.039 in both of them; so I stirred the yeast cake back into the beer thinking this was obviously not a complete fermentation. Fast forward to today, the gravity has not budged and is still identical in both of them even though they are different yeast strains. If they are not done fermenting I feel like they are probably close... but I do have a 2L starter of WLP099 already made for just such an occasion.

Are they done fermenting or was it a weird stroke of luck that they both finished at the exact same gravity and I should pitch the 2L of WLP099 between them?

 

[HopJuicer]

I had a chocolate milk stout stall at 1.038 and 1.042 from a split 10 gal batch. I used wl London and wl Edinburgh for mine. Org was 1.07 for mine and I too had 3# lactose. I split a starter of the wl super high gravity and it brought one down to 1.020 and the other to 1.016. I laughed at how close that sounded to my experience.

I think you can drop some more points but hopefully someone else can chime in too

 

[ChessRockwell]

Looking at your recipe I think you've answered your own question, I'd say that's probably about as far as it's going to go. Although 2 1/2 weeks isn't really long enough, so it COULD go further... If warming up, rousing the yeast, and allowing more time doesn't work, there are a few things I might consider doing... (others opinions may vary)

1) Adding simple sugar. You're at less than 7% now and adding a couple pounds of simple sugar could raise the abv and dry it out a bit.

2) Go buy a pouch of Wyeast 3711, make a nice starter, and pitch it in there. Someone on here once said that stuff will ferment your brew paddle if you leave it in there too long... Although this runs the same risk as adding an amylase enzyme, in that it could ferment too much, and a really really dry imperial stout could be nasty. But if it's undrinkable as is, what have you got to lose? I'd go this route before adding beano tablets...

EDIT: Looks like the person above me had a really similar experience, I'd try that before my ideas

 

[Vertra]

So I think since I already have 2L of WLP099 handy ill just decant and split that, boil up a pound of sucrose and some yeast nutrient per fermenter and pitch it all with some good aeration. 1L of active WLP099 with nutrient and aeration should be able to finish this off I think. Thanks for the suggestions.

 

[HopJuicer]

I was wondering if you pitched the wlp099 and if you had any results?

 

[smokinghole]

Based on your fermentables I don't think it's just stalled I think it's done with the given yeast strains. You're at like 56.6% attenuation as it stands. Then you have damn near 10% lactose. So that probably puts you near the low end of attenuation just with the lactose addition alone. The rest of the residual sugars could very well make up an additional 10% or more of unfermented sugars.

I think it's done but that doesn't mean it's done for WLP099. That stuff will chew through I think at least another 10 points of gravity I think for you if not 20 points. You just need to give it ample time to finish because it does work fairly slow. Also when it comes to pitching the WLP099. I'd pitch 2L in each fermentor. Grow then crash it and decant the liquid off so you don't dilute your beer. Give each fermentor the nice thick slurry from the 099 and wait a good while. Make sure you check for terminal gravity with a hydrometer to ensure its finished. I've had 099 slowly work after two months in a bottle when I thought it was done and ended up with seriously overcarbed beer (it was a total accident I used 099 to begin with though).

 

[Calder]

As others have said, I think you are done.

I would have recommended using 3711, but I have no experience with 099. Since you have 099, and others think it is good, you should try it.

Do NOT aerate the beer! Only the starter should be aerated.

I would decant your starter, split it into 2 1-gallon containers and add 2 liters of wort to each. Let it ferment (like a beer, no aeration after initial pitch), once it is going, add 2 liters of the beer to each starter (again no aeration) and let it get working on that. Once the starter seems to be fermenting fine, add the starters to the stuck beer. Just pitching yeast into a 7% beer, will be slow to get to work, if it works at all.

 

[Vertra]

I repitched the 099 5 or so days ago and I am still getting some activity in the airlock (4-5 bubbles per minute). I threw in a pound of simple sucrose and a double helping of yeast nutrient to get it going. I am not expecting gravity to drop below 28 or so but we will see what happens.

I did aerate the wort however on the suggestion of a master brewer I know. He said there is no harm in it since the yeast will use it all before it has a chance to oxidize.

 

[smokinghole]

Your starter would have had enough oxygen going into the fermentor. You also wouldn't have needed the pound of sucrose not with 099 on the job. That yeast is a serious wrecking crew. Let us know how it turns out.