Stuck Fermentation

[STL_Lucas]

I brewed an Irish Stout last sunday 11/10 and pitched some Wyeast #1084 yeast that I had on a 36 hour starter. The OG was 1.046 and when I checked the SG on Sunday 11/17 it was only at 1.026. Decided to wait a couple more days and checked again tonight and still reading 1.026. This would be my first stuck fermentation and not really sure which route to take. Should I try to stir everything up and add some yeast energizer or just pitch another packet of dry yeast? Any tips would be appreciated. Thanks in advance!

 

[hercher]

Can you give us a little more information? What was your recipe? If all-grain, what temperatures did you mash at? What temperatures are you fermenting at?

 

[STL_Lucas]

This was an extract recipe from Midwest Supplies. Pitched yeast at about 60*F and have held ambient temp in swamp cooler to around 60*- 65*F.

6 lb. dark liquid malt extract
4 oz. Chocolate Malt
4 oz. Caramel 10L
4 oz. Roasted Barley
4 oz. Flaked Barley
1 tsp. Gypsum
1/2 oz. Nugget
1 oz. Willamette

 

[BrewinBromanite]

I don't know the extent to which this will account 100% for your higher than anticipated FG, but I know that the Dark LME will have quite a bit of caramel/crystal malt along with base malt. As far as how much / what ratio is in your exact LME, that I don't know. But you do have more crystal in addition to the separate small amount of crystal you steeped. This could be one factor in the high FG. It's possible that this is as far as will get down to with your recipe, considering it sounds like you had a good starter and good temp control. You could try warming up the temp closer to 70, and rouse the yeast a bit, just in case you got it too cold and put the yeast to sleep.

 

[STL_Lucas]

It was supposed to finish around 1.010 or 1.012. Should I pitch another packet of dry yeast or add anything?

 

[duboman]

I would raise the temp and rouse the yeast first. Also be sure your hydrometer is calibrated properly: 1.000 in 60F distilled water, make any adjustments if necessary. If using a refractometer try the hydrometer.

 

[k_mcarthur]

It was supposed to finish around 1.010 or 1.012. Should I pitch another packet of dry yeast or add anything?

Your yeast you already have in there aren't dead, just unhappy. Pitching more would just add more unhappy yeast once they adapt to the environment the others have. Like suggested warm it up and rouse the yeast cake, if that doesn't do anything after 4-5 days you are likely not going to be able to ferment any more sugars. With all that dark roasted grains I don't think you'll get down below 1.020.

 

[TungstenBeer]

That yeast strain is supposed to be fermented in te 62-72 range according to Wyeast's website. In my personal experiences, sometimes even the low range (in this case 62-63) could result in a very slow fermentation, so if you're at times down around 60, I'd be pretty confident temperature is the issue. If you can get it closer to 68-70 as others have said I bet activity will start up again.

 

[hercher]

The above posters, I think, have hit the nail on the head. To summarize:

1. Your recipe seems to have a lot of unfermentable sugars. You probably should have added some light malt extract, or done a mini-mash with some Vienna or Munich malt.
2. You are fermenting a little on the cool side. Warm it up a little.
3. After you've warmed it up, give your beer a GENTLE swirl to get the yeast back in suspension.

 

[STL_Lucas]

Thanks for the help guys. I think the reason I was trying so hard to get the temps down is because my first couple of beers fermented too warm and had heavy banana flavors. I guess in trying to be diligent to hit 60 on this one i went too low. Also a little disappointed that Midwest Supplies would sell a prebuilt kit with unfermentable sugars or with a recipe that wasn't designed to ferment all the way. Working on warming up and waking up these yeast!

 

[BrewinBromanite]

Just to follow up a bit. I think it is very admirable that you've tried so diligently to ferment on the cool end of the range for the yeast!! I was in the same boat after my first couple batches of following the directions that came with my kit just "stick in a cool dark closet" and hope for the best. I too had some pretty bad off-flavors as a result of high initial fermentation temps.

Once I got a good handle on temp control - especially during the first 2-3 days of fermentation - quality improved dramatically. But it is possible, especially with some yeasts' flocculation properties, that too cold of temps will make them drop out a bit prematurely. I'm now a firm believer of fermenting for the first week or 2 on the cool side - just watch that it doesn't drop much below the far end of the cool range. Then warming up slowly for another week or 2 to 65-70 to finish and clean up a bit.

If you warm up to 68-70, then rouse the yeast, the wait a couple days to see if gravity drops a little, it may very well help out. If not, it's probably just a good amount of un-fermentables that may not go much lower. Doesn't mean it will be bad beer. May be very good in fact. Until you move to partial mashing or all-grain, you kind of have to live with the proportion of crystal that is part of extracts and account for that.

Of course, another option might be to use lighter extracts, and then compensate with steeping darker grains to get the same effect. Ie...for your recipe, use light or extra light extract, and steep with a little dark crystal or roasted barley or some chocolate malt, rather than using the dark extract. Anyways, I'm sure it will still be good beer! Let us know how it turns out!