Persistently Stuck Fermentation

[cernst151]

I know that there are some threads on stuck fermentation out there but I've already tried a lot of the suggestions out there and I want to know if there's anything left I can do.

It was a stout recipe I've used before and it was the second time (first generation) I've used recycled Safale 05 from another batch (the other batch that used that recycled yeast went down below my target FG in 1 week). I made a starter with 2 cups water and .5 cup DME and had let it sit a few days to get going.

This is a coffee stout, partial mash. I don't have the recipe in front of me but I'll try to post it tonight when I get home. It started around 1.08 or 1.09 OG and went down to 1.044 in the first week then stopped. I gave it a few days then stirred up the trub and it started bubbling again and got down to 1.036 over the course of a week. After another week it was still 1.036.

At the advice of my LHBS I pitched a pouch of Saisson yeast to clean it up and after a week it's down to 1.034. I've stirred again and added about 1tsp (it's all I had) of yeast nutrient. The only other suggestions I've seen that I haven't tried are to add sugar and yeast hulls and I may do that tonight.

Any other suggestions would be greatly appreciated. I bottle in glass and don't want any bottle bombs. If I bottle this as is am I going to have beer and glass shards all over my basement?

 

[Effingbeer]

I'm thinking get a new hydrometer; or are you measuring with a refractometer and not doing the calculation? I would think it's almost impossible tho have that high of an FG after all you've done. Unless you got some pretty unfermentable extract.
1st I would rule out the measuring device.

 

[cernst151]

I'm thinking get a new hydrometer; or are you measuring with a refractometer and not doing the calculation? I would think it's almost impossible tho have that high of an FG after all you've done. Unless you got some pretty unfermentable extract.
1st I would rule out the measuring device.

That seems pretty unlikely since the IPA I just moved to secondary, sparkling wine I just moved to secondary, and white wine in primary are all showing different numbers and all right on target with that same hydrometer. I do have another hydrometer though so I'll give it a shot just in case.

 

[Johnnyhitch1]

Only thing i can think of is that you either mashed to high or have way to much crystal/roasted malts in your grain bill
Throw up the recipe.

 

[cernst151]

Johnny, I hope you're right. If it's just too much unfermentable sugar I'm perfectly fine bottling it. I just don't want to bottle it and find the yeast suddenly wakes up and I end up with shrapnel in my walls.

 

[cernst151]

Great news! I added 3/4 cup of table sugar along with 2.5tsp yeast energizer http://www.northernbrewer.com/shop/yeast-energizer.html to the primary fermentation on the 16th. Of course I boiled it in some water to sanitize. Now, 6 days later I've gone from 1.034 (where it had been stuck for about 2 weeks) down to 1.024 and it's still bubbling.

I can't be 100% sure if it was the sugar or the yeast energizer, or if it needs to be some combination of the two, that did it but it worked. I'll come back later to let you know what final gravity I ended up with.

The next problem I'm going to have to solve is that since I've stirred the trub up into suspension a few times it's all mixed back into the beer. I hope that cold crashing will get that all to drop back to the bottom before secondary and bottling. Any tips for that?