Dry stout, stuck fermentation...

Well, it finally happened to me. Brewed a dry stout a few weeks ago, pitched Wyeast Irish Ale from a starter, all appeared to be going fine. Had what looked like a nice fast fermentation at about 65 degrees, however after two weeks I checked the gravity and it was at 1.020. I roused up the yeast and brought the beer up to about 72 degrees, had what appeared to be a small amount of activity. Checked the gravity again in a week, still 1.020. At this point I pitched a packet of Nottingham and a small amount of sugar solution and yeast nutrient into the carboy. Within hours there was some very obvious activity. Checked the gravity a week later, still 1.020. I then transferred the beer to secondary, taking a lot of the yeast cake with it, hoping that would stir things up, however after a week, I'm still at 1.020. I guess all I can do is rack it onto a yeast cake from a different beer, or make a huge starter?

This was an all grain batch, recipe as follows:
6.0lb Marris otter
2.5lb Flaked Barley
1.25lb Roasted Barley
2oz Acid Malt
2.5oz Goldings, 4.5% @ 60min

Wyeast 1084 Irish Ale

5.5 gallon batch, 60 minute mash @ 152, 60 minute boil, OG 1.052.

Had a great brew day and nothing went wrong, had full conversion, great boil, hit my numbers spot on. I really don't understand why this thing won't budge. Ideas?

I've had and heard about lots of people having issues with stouts stopping at 1.020. These were usually sweet/milk stouts though. It sounds like you've done a good amount of work trying to rouse that yeast. I'm going to assume it's done.

What kind of thermometer are you using? You can try using Amalyse Enzyme to bring it down. Maybe you inadvertently mashed too high. That's happened to me with a bad (short) thermometer.

I've got a digital thermometer that has a pretty long probe on it, has always been accurate in the past, so i don't think that is the issue (hopefully). I thought about amalyse enzyme, but I have read that it takes a long time to dry a beer out with that. I was hoping to have this ready to drink by march 18. It is totally drinkable right now, just has a lot more body than I wanted it to.

Did you measure toward the top of the mash or toward the bottom or middle? Will you be kegging this or bottling? If you're kegging you could do amalyse. I think I just let mine sit for a couple weeks then checked on it - not sure how long it really took. If you're bottling you're going to have to bottle now if you want it ready by then.

I measured towards the middle, and I will be kegging this one. It will probably be gone within a day or two since I am bringing it to my friend's place for a party, so it doesn't have to be perfect. It would be nice if it were drier though, to make it a bit more sessionable/less chewy.

Well in that case I would try amalyse enzyme and let it go and then force carb for the remaining week to week and a half. That's what I would do at least. Doesn't look like it was a mashing problem. I do know that the Irish Ale yeast isn't the best for Dry Stouts, since it doesn't attenuate very dry. I actually had a Dry Stout with that yeast start and end the exact same as you, although I was still using my short thermometer. I just kegged it and drank it though. I think I was in a hurry.

Do you think its worth racking it onto another yeast cake before trying the Amylase?

If you have one yea it's worth a shot.

I just brewed a recipe simliar to this, same yeast too. Mine fermented really slowly (on the 4th day now) and its dropped from 1.063 to 1.038 only. Its going very slowly. Honestly I think your beer is just done fermenting... there is probably a lot of unfermentable sugars left in your beer and its not going to ferment anymore. My advice would be to just leave it and continue on with bottling/kegging it. 1.020 is a good FG for a stout IMO.

Have you tasted a hydro sample? I'm sure it tastes good!

robertvrabel said:

I just brewed a recipe simliar to this, same yeast too. Mine fermented really slowly (on the 4th day now) and its dropped from 1.063 to 1.038 only. Its going very slowly. Honestly I think your beer is just done fermenting... there is probably a lot of unfermentable sugars left in your beer and its not going to ferment anymore. My advice would be to just leave it and continue on with bottling/kegging it. 1.020 is a good FG for a stout IMO.

Have you tasted a hydro sample? I'm sure it tastes good!

Click to expand...

It is pretty good now, I was just hoping for it to be a bit drier.

jaba said:

It is pretty good now, I was just hoping for it to be a bit drier.

Click to expand...

I don't know how this works for sure... but I'm assuming the barley doesn't have as much fermentable sugars available as the Marris Otter does... so since its a large percent of your recipe, that is probably why your left with some unfermentables and stuck at 1.020.

Like I said, I'm not 100% sure on this... but I'm just going off my first experience with a similar recipe and thought I'd share.

What if you pitched some champagne yeast...that should dry it out right?

It probably would've.... needless to say, this beer is long gone... almost a year ago.