Stalled Fermentation - Smack pack insufficient?

Can you please provide more details on your mashing regime? For example, what temperature did you mash and how long did you mash?

Cheers!

 

Smack pack should be just fine for a 5 gallon batch. How long did you allow the smack pack to sit and create your starter before the pitch? What temperature did you pitch at? What temperature did you mash? What yeast variety did you pitch?

 

222B cells are recommended for 5.5 gals of 1.058 wort. You pitched about 80B depending on the age of the smack pack. Sometimes this works. Sometimes it doesn't. Doing a starter and pitching more yeast improves the odds of success.

It's also possible your wort is less fermentable than you intended.

 

That is an ESB with an Attenuation of 67-71%. You established your software baseline for an attenuation of 72%
Wyeast (London ESB Ale™) - 1968

Your FG is in the ballpark...

 

Generally speaking a mash temperature of 152 degrees F for an hour-ish should create a fermentable wort. The other potential variable is the specific malt you used; maybe that specific malt will still have a fair bit of dextrins even when mashed at this temperature?

Do you recall the packaged date of your smack-pack? Which yeast strain did you use?

Cheers!

 

Is there a reason that you think his attenuation should be 67-71%?

Cheers!

 

Wyeast (London ESB Ale™) - 1968

 

OK so I clicked on the link to ‘discover’ that the yeast strain is 1968.

In the description Wyeast does mention: “Attenuation levels are typically less than most other yeast strains which results in a slightly sweeter finish.”

They do publish a ‘spec’ of: “Attenuation: 67-71%” but frankly I take numbers like this with a grain of salt since what attenuation is achieved is also a function of the fermentability of the wort and is not just a function of the yeast strain.

I have used 1968 in the past but that was something like 15+ years ago. I have no recollection of what level of attenuation I achieved with this yeast.

Maybe some other BAs who regularly (or more recently) brewed with 1968 yeast while mashing at 152 degrees F can provide some input here.

Cheers!

 

Have you brewed with 1968? If so, what attenuation did you achieve (with a 152 degree mash)?

Cheers!

 

Running your recipe/process details through BrewCipher, which considers grain bill, yeast strain, mash length, and mash time, and it predicts a 1.013 FG for an OG of 1.058.

1968 is not the wimp implied by a 67-71% published range. And 152F is almost as fermentable as it gets (from a mash temp factor perspective) for single infusion mashing.

 

Nope, have you? My yeast of choice is White Labs 007.

 

At the 2112 National Homebrewers Conference, Greg Doss of Wyeast gave a presentation entitled “Exploring Attenuation”. Within that presentation he studied the attenuation of 51 different Wyeast ale yeast strains using a common media (wort). The average attenuation of those 51 strains was 76.70%. Wyeast 1968 is a tad below average at bit over 76% for that given media (wort). As a basis of comparison Wyeast 1056 had an attenuation of 77.35%.

I don’t know the specific malt used for “British pale ale malt” but as I already mentioned generally a mash at 152 °F typically creates a fermentable wort.

Cheers!

 

1968 attenuated 76% in a forced fermentation test done by Gregg Doss of Wyeast. It would be nice if Wyeast updated the specs on their website someday.

 

Yes I have but as I previously posted it was so long ago (15+ years) it have no recollection of its performance.

Another thought just popped into my mind. Wyeast 1968 is an "extremely flocculant yeast" so when I did brew with it I made it a practice to rouse (gently swirl) the yeast in my fermenter for several days (e.g., days 3-6 of the primary) to make sure that the yeast did not settle out prior to the primary fermentation being complete.

@chrisjws, did you take any measures to ensure that the yeast did not flocculate out prematurely? Maybe the yeast settled out before getting the job done? I wonder if it makes sense to try the rousing method now to get the yeast to 'finish the job'?

Cheers!

 

I would rouse the yeast and raise the temperature to 70 degrees for a few days to see if I got any activity as @JackHorzempa said he has done in the past.

 

What I did when I brewed with 1968 so many years ago was to gently 'swirl' my primary fermenter with the notion to get the yeast back into suspension so that it would continue to 'work'. It sounds like your fermenter has been 'sitting' for quite some time but maybe rousing/swirling will re-awaken your yeast and get them working again?

Another step you could take is to add some more yeast (e.g., a packet of dry yeast) to get that yeast to consume the remaining sugars. I am personally not a fan of mixing yeast but since the added yeast will only doing a bit of the 'work' maybe there would not be much impact to the flavor?

The other option is to just accept the beer as is with a FG of 1.022.

I would suggest you give the rousing a try for a few days and then decide from there.

Cheers!