us-05 stuck fermentation?

[simejack]

Hi everyone, I'm have a slight problem with latest batch and was hoping for some advice -

Decided to brew a session IPA but didn't have time for a starter so I used us-05 (for the first time in years!).

I properly rehydrated, pitched a full packet in 19L of 1.044 wort (maybe a little higher, I forgot to adjust for temperature) at 17C (36 F) and fermented at 18C (65F) for thee days before ramping to 20C (68) for the last week.

So the problem... It's nearly 10 days in and my gravity reading on only 1.020! Lag time was only 18 or so hours and fermentation seemed pretty vigorous for the first few days. I mashed slightly higher than expected at 69-70C (156-158F) but I doubt that this is the cause. My only thought was that dumping the trub at +40ish hours maybe dumped a bunch of yeast also? It's a new setup (my first temp controlled conical) so I'm not quite used to the process yet.

Anyway I was hoping for some advice - should I bother trying to pitch more yeast? Any chance the beer will be drinkable anyway? Any idea what on earth could have caused this?

Thanks for any help!

 

[MyQul]

So you opened the dump valve of your conical after about 40 hours? This might have caused the problem. That would be like racking to a secondary after the same amount of time.
Mashing so high wouldn't have helped either. Your right that the high mash possibly wouldn't have caused the stuck ferment alone as us-05 has such a high attenuation but perhaps the combination of a high mash plus removing it from the trub could have caused the high FG

 

[cheapbrew]

If it is due to removing the trub early then pitching more yeast might work, but if the higher mash temp produced more unfermentable sugars it might not, quite a few people here mash at those temps without problems though so the most likely action seems to be add more yeast.

 

[Covrich]

I agree with MQ, I think its probably a combination of both.. you could pitch more and it may shift a little more but with a high mash it will be what it will be I guess

 

[simejack]

Thanks guys - it probably was the combination. The trub dump was only 500ml or so and mostly cold break (I cooled in the FV); but silly none the less. I'll try pitching more, I guess it can't do any harm?

 

[Simonh82]

I also had issues with a stuck fermentation with US-05 recently. My mash temp was fine but I screwed up my water chemistry leading to a really low mash pH. If done some more reading up on this and it seems this can lead to low attenuation.

Mine stuck at 1.015. I started at 1.044 and was aiming for 1.008. I followed a very similar fermentation temperature profile to you. I roused the yeast and really got everything that was at the bottom back in to suspension. This lead it to drop to 1.012 over a couple of days but no further.

I would try giving it a good (gentle) stir and get whatever yeast is in there back in to suspension. I also bumped the temp to 22 degrees.

Good luck!

 

[simejack]

Glad to hear it's not just me! But thanks that's really helpful, I hadn't considered the mash ph. It did measure a litte low (5.0 mash temp 5.3 room temp) but my ph meter is far from reliable so it could have been worse. I have pitched another pack of us-05 (overkill, but no harm done), given it a good swirl and raised the temp to 21C - fingers crossed.

 

[Simonh82]

5.3 at room temp sounds spot on. Mine was 4.6 at room temp! I was pointed in the direction of some interesting information on this site. The link goes directly to a table of mash pH and attenuation and efficiency but there is more information further up the page.

 

[TartanSpecial]

My only thought was that dumping the trub at +40ish hours maybe dumped a bunch of yeast also? It's a new setup (my first temp controlled conical) so I'm not quite used to the process yet.

The benefit of a conical is that the surface area of trub in contact with the wort is low, so there is no real need to dump it before the fermentation is finished. I've got an SS brewtech chronical conical and I find that by the end of the fermentation, the combination of trub and settled yeast come up to only a couple of centimeters below the racking arm, so when I drain the fermenter via the racking arm I lose very little beer.

 

[simejack]

5.3 at room temp sounds spot on. Mine was 4.6 at room temp! I was pointed in the direction of some interesting information on this site. The link goes directly to a table of mash pH and attenuation and efficiency but there is more information further up the page.

Maybe not that then! Interesting link though - even the slightly low ph's seem to have low attenuation.

 

[simejack]

The benefit of a conical is that the surface area of trub in contact with the wort is low, so there is no real need to dump it before the fermentation is finished. I've got an SS brewtech chronical conical and I find that by the end of the fermentation, the combination of trub and settled yeast come up to only a couple of centimeters below the racking arm, so when I drain the fermenter via the racking arm I lose very little beer.

Thanks also! The problem is I wanted to avoid transferring to a secondary to add the priming sugar. I'm considering just biting the bullet and buying a keg though, in which case I'll get to do exactly that.

 

[MyQul]

Thanks also! The problem is I wanted to avoid transferring to a secondary to add the priming sugar. I'm considering just biting the bullet and buying a keg though, in which case I'll get to do exactly that.

You can add priming sugar no problem. I almost always just batch prime the primary then bottle. Just very carefully stir the priming sugar in and try to make sure you don't touch/disturb the trub. Then leave it for 30 mins so any trub you may have disturbed settles back again, before packaging

 

[simejack]

You can add priming sugar no problem. I almost always just batch prime the primary then bottle. Just very carefully stir the priming sugar in and try to make sure you don't touch/disturb the trub. Then leave it for 30 mins so any trub you may have disturbed settles back again, before packaging

That's great to know. I'm pretty scared of not mixing the priming sugar properly again, but if it settles that fast it won't matter. I can cold crash now so I guess it's even less of a problem. Thanks!

 

[Simonh82]

Also there is nothing to stop you clearing the trub before you bottle but after 40 hours sounds too soon.

 

[simejack]

Also there is nothing to stop you clearing the trub before you bottle but after 40 hours sounds too soon.

I was worried about clogging, I've heard this is a problem with the the brewtech conicals (on top of which most of the boil hops may have made it into the fv...). But yes 40 hours was definitely too soon!