Lager Fermentation Stuck

[tezcatlipoca]

Hi guys,

I have a Baltic Porter, OG of 1.096 that was brewed on 11-10-18. I fermented this at 52F until 11-21. I let it warm up to 68F over a day and kept it there until 12-2-18. Then, I crashed it to 34F because I expected that it was done. I do try to limit my gravity samples. Before transferring to a keg to lager, I took a sample and found my gravity to be 1.034. This is very unexpectedly high considering it has been going almost a month. My sample tasted amazing though!!! Everything that I'd want in a high abv Porter, minus some extra residual sweetness.

I made a 2 Liter stir plate starter with three packs of yeast, which seemed close to what Mr Malty wanted. It would've been spot on if one/two packs had a more recent manufacture date.

Do I repitch more yeast? Do I just let it warm back up to 68F again? I would definitely prefer a FG under 1.020. If I repitch, should it be ale or lager yeast? I know most lager yeasts struggle above 9%. Any other suggestions?

Regards,


Charles

 

[Rob2010SS]

What yeast did you use?

I'm not familiar with the baltic porter style, is it typically fermented as a lager?

Personally, my first step would be let it warm up and rouse the yeast by swirling the fermenter. Give it a couple of days. If that doesn't work, you could try and pitch something like US-05 to see if it will drop it down. I haven't had much success restarting fermentation. I had a stuck fermentation once and I tried...

1. Rousing yeast
2. Pitching starter at high krausen
3. Pitching rehydrated US-05

Didn't do anything for me. But if you legit still have some sugars in there to consume, one of those should work for you.

 

[tezcatlipoca]

What yeast did you use?

I'm not familiar with the baltic porter style, is it typically fermented as a lager?

Personally, my first step would be let it warm up and rouse the yeast by swirling the fermenter. Give it a couple of days. If that doesn't work, you could try and pitch something like US-05 to see if it will drop it down. I haven't had much success restarting fermentation. I had a stuck fermentation once and I tried...

1. Rousing yeast
2. Pitching starter at high krausen
3. Pitching rehydrated US-05

Didn't do anything for me. But if you legit still have some sugars in there to consume, one of those should work for you.

It is typically a lager. I used German Bock, Oktoberfest lager, and bavarian lager yeast.

I definitely have sugars left; I just hope they're fermentable. 1.034 would be way too sweet for me to drink this. I'm letting it warm up now and I'll try to rouse the yeast when I see it later today.

 

[jfolks]

The concern is adding a non-lager yeast my make it taste like a non-lager. Bring it up to 50, add that enzyme everyone is using for Brut IPA, and maybe add more lager yeast

 

[cactusgarrett]

Hmmm.... I've never had attenuation issues with those strains. Did you check the grav before you warmed it? I'm assuming you warmed for a diacetyl rest? Usually this is done after ~75% of fermentation has completed, and the warmth helps with momentum to get that final 25%. Another concern is that the yeast flocced out before finishing.

I would not add the enzyme - that could take it down too low and swing the pendulum towards too dry for the style. As Rob mentioned, i would bring it back up to 65°F and gently rouse the yeast over a few days. Also, adding US-05 could be a good idea, and at this point won't affect the flavor. The majority of the ferment is done, and another 10+ points won't contribute ale-like flavors to the lager. It shouldn't be an issue, either, due to the robust flavor profile of a baltic porter. MAYbe you'd be able to detect something in a softer style - like imperial pils or something of the sort - but i doubt you would here.

 

[tezcatlipoca]

Hmmm.... I've never had attenuation issues with those strains. Did you check the grav before you warmed it? I'm assuming you warmed for a diacetyl rest? Usually this is done after ~75% of fermentation has completed, and the warmth helps with momentum to get that final 25%. Another concern is that the yeast flocced out before finishing.

I would not add the enzyme - that could take it down too low and swing the pendulum towards too dry for the style. As Rob mentioned, i would bring it back up to 65°F and gently rouse the yeast over a few days. Also, adding US-05 could be a good idea, and at this point won't affect the flavor. The majority of the ferment is done, and another 10+ points won't contribute ale-like flavors to the lager. It shouldn't be an issue, either, due to the robust flavor profile of a baltic porter. MAYbe you'd be able to detect something in a softer style - like imperial pils or something of the sort - but i doubt you would here.

I did not check the gravity before warming it. That's my bad. I mean, it had been weeks, but I could've been more patient.

It is definitely a possibility yeast flocced early. Before I warmed it up, it seemed like all yeast was out of suspension.

I am trying to rouse the yeast now. I'll probably take a gravity reading Friday night to see if it's moving.

Thanks for the advice guys!

 

[cactusgarrett]

No, you DO want to check it early if you're shooting for a diacetyl rest. I just used WLP830 for a festbier, for example, and it took 6 days to get down from 1.055 to 1.023 - at which point i started to warm it. I'm expecting it to get down to 1.012. You want to hit that 25% remaining mark to warm it.

 

[RM-MN]

Do I just let it warm back up to 68F again?

68 may still be too cold to get the yeast excited enough to finish the ferment. Swirl the yeast back into suspension, warm the beer to mid 70's and let it stay there for a week or more.

 

[tezcatlipoca]

Looks like it's at 1.030 right now, so I'll keep rousing the yeast and keep it at 70F and relax, have a Homebrew!

 

[couchsending]

How much yeast did Mr malty tell you to pitch? How old were the packs? How long did the starter go for? What was your mash profile? Pure O2? Shake method?

I think you’d be surprised how high most dark beer of this ABV actually finish. Have you degassed and measure your favorite Baltic Porter?

If you pitch enough yeast and aerate well you never need to do a diacetyl rest with lagers. They can consume diacetyl at incredibly low temps.

 

[tezcatlipoca]

Only one pack had any real age on it. Currently, my gravity is at 1.022, so I guess I'll relax, have another Homebrew and wait for this to finish out. I think it'll get close to the 1.016 that was planned at this rate; it'll just take time.