Wyeast 1968 stops early?

[MadZack]

I'm on my second batch using Wyeast 1968 (London ESB). The first was a partial-extract pumpkin porter, and this one is an all-grain ESB. In each case, the fermentation completely stopped long before it should have, at about 60% attenuation, resulting in a stuck fermentation.

For the first one, OG was 1.078, and FG was 1.031, an apparent attenuation of 60%; desired FG would have been 1.024. For the ESB, OG was 1.060, and FG was 1.024, to yield an apparent attenuation of 60%; desired FG would have been in the late teens, say 1.017.

Wyeast claim an attenuation range of 67-71 for this strain, which in each case would have gotten my FG down to the desired spot.

Am I just getting unlucky? I nailed the mash on my ESB, so and the pumpkin porter was extract, so I'm pretty confident in the sugar content going in...

I've brewed plenty of batches with other Wyeast strains (I use them almost exclusively, save for an occasional Nottingham batch), usually with 1056 and 1272 (American Ales), with a couple batches of 1084 (Irish Ale) as well, and I've never had problems with these less-flocculant/higher-attenuating strains.

The ESB is still in primary currently, but it has been 3 days at the same SG, so I'm pretty sure it's done. I tried a gentle swirl of the fermenter when I first noticed fermentation had tapered off, and have done this twice since, doesn't appear to help restart.

Should I try pitching a more-attenuative yeast onto this batch, to "finish" it? Maybe 1318 (London Ale III)? Or Nottingham? Or S-04?

 

[JonM]

I use that strain a lot and I really like it, but it does need some TLC to keep it from stopping early. When fermentation starts to slow (which may be as little as 18-24 hours after it starts) I start to warm it up - adding 2° F every 8-12 hours until it's 70ish. That always does the trick for me at least.

 

[MadZack]

I use that strain a lot and I really like it, but it does need some TLC to keep it from stopping early. When fermentation starts to slow (which may be as little as 18-24 hours after it starts) I start to warm it up - adding 2° F every 8-12 hours until it's 70ish. That always does the trick for me at least.

Thanks for the quick response!

Interesting. For my most recent batch, temperature may have been part of the concern, as fermentation dropped to 63º at one point for a couple hours (my remote control on the heater lost its internet connection while I was away for the night...), which is less than ideal. That was about 2 days in, after a lot of the SG drop had already happened. I'm currently at 66º, and was hoping to stay around there, as I'd rather steer clear of the estery/fruity flavours that 1968 can produce at the higher range, but maybe next time I'll try keep the temperature up during the beginning.

I just used the normal smack-pack instructions, I did not do a starter. Do you usually do a starter with this yeast?

Any suggestions how I should proceed with this stuck on?

 

[JonM]

It's a great strain, but it can be a finicky SOB. If you can warm that current batch into the low 70s, that might help. It's an extreme floccuoator, so maybe take a sanitized racking cane and gently stir up some of the settled and compacted yeast from the bottom of the fermenter. (Warming it up at this stage won't produce eaters; those only form at the very beginning of fermentation.)

ETA: yes, I always use a starter with this yeast. Keep it happy, and it'll be good to you.

 

[MadZack]

It's a great strain, but it can be a finicky SOB. If you can warm that current batch into the low 70s, that might help. It's an extreme floccuoator, so maybe take a sanitized racking cane and gently stir up some of the settled and compacted yeast from the bottom of the fermenter.

ETA: yes, I always use a starter with this yeast. Keep it happy, and it'll be good to you.

Good idea, I'll give both a try, and see how it goes. Thanks!

 

[Murphys_Law]

I just used this the first time for my ESB and went from 1.056 to 1.017, which was my FG target. I fermented at 68 and raised to 70 after about a week. I let that sit for a few more days and Kegged.

Edit: I used a starter.

 

[kristiismean]

JonM nailed it. Temp control with that strain keeps it happy. I was going to say bump it up to 70-72...

 

[coypoo]

I will swirl my bucket to get things back into suspension (rather than open it up and stir it)

 

[stevehaun]

Grain bill?
Mash temp?
It is really hard to comment on your FG without knowing those variables.