Stout stalled after 5 days

[Bvk1983]

The stout I brewed 7 days ago stalled after 5 days. OG was +/- 1.140 but after I added al large yeast starter it dropped already to 1.120. The yeast starter was 3 liter, White Labs WLP099 Super High Gravity. I didn't aerate actively because my aeration pump wasn't delivered yet but I rocked the vessel heavily before pitching the yeast. I was already afraid this would happen because the WLP099 was nearly a year old when I got it delivered.

It stalled at 1.084 so it didn't work very hard. To boost the fermentation I added two packages of US-05 yesterday but to this moment (nearly 24h after pitching) the fermentation isn't doing anything.

Is there something I can do to get it going or is this a lost batch of stout?

 

[Erik The Anglophile]

How did you mash it? What was the grainbill like?

 

[Bvk1983]

I did a double mash at 65C for 75 minutes each. This was my grain bill:

 

[Erik The Anglophile]

It should ferment down more since you mashed pretty low and slow, even with that amount of crystal.
I'd try rousing it a little and see if anything happens.

 

[Bvk1983]

Would it be useful to aerate actively at this moment or won't that make a difference?

 

[peebee]

1.120 - 1.140 will seriously stress the yeast (ask a winemaker!). Throwing an out-of-date liquid yeast at it may have been asking for trouble? The US-05 had only been given 24 hours? A far less stressed "stuck" situation I added S-04 to took 6-7 days before fermentation took off again. US-05 may not have the alcohol tolerance to do the job (only 11% ... !) but give it a lot more time than you have.

I have seen suggestions to aerate strong beer later into fermentation, but it's not usually considered to be a good thing.

 

[Bvk1983]

I grew some more yeast cells in the starter but obvious not enough. I had some doubts about the date of the yeast but some people at the Dutch homebrewing forum ensured me that a 3 liter starter would do the job...

The reason I added US-05 is because I assumed it could handle the current gravity of 1.084. I added 2 packs on 13 liter so that should be sufficient. Would it help if I added a little amount of sugar so the US-05 can multiply on the sugar? Let's hope it will start again.

 

[foxy]

Would it be useful to aerate actively at this moment or won't that make a difference?

Not a good idea to aerate again. The 05 you added doesn't need any oxygen to get started, and at the gravity you are at there would be no need to add sugar.

 

[allotment_fox]

Presume your pitching temperature and conditions are all ok, basic I know as you rocked it about there should have been enough oxygen to get it moving , so don't see anything other than a yeast issue