Kick starting a stuck doppelbock

[chumley]

I brewed a 1.090 doppelbock 5 weeks ago, using WLP810 San Francisco lager yeast, and after three weeks of no activity, I have concluded that it is stuck at 1.032.  I would like to get it down another 4-6 points if I could.

Nine days ago, I brewed a 1.052 pilsner, and split the batch between WLP833 German Bock and WLP940 Mexican lager yeast.  Both are in a temperature controlled freezer set at 50°F.  The 833 is still chugging away, but the 940 is done.

I also have available a half gallon (growler full) of unfermented bock wort.  I grabbed it the day after I brewed, from the bit under the false bottom.  My thought is to boil up that half gallon of wort to ensure it is sanitized, adding a pint of water to knock the gravity down from 1.090 so it wouldn’t shock the yeast.  Then I would rack the pils, aerate the wort, then add it to the now empty primary with 940 yeast cake.  After a day, when it gets back to high krausen, I would add that to the stuck beer and swirl that in gently, in hopes to restart.

I am welcome to suggestions to improve my proposed plan.

[wort-h.o.g]

@chumley

I brewed a 1.090 doppelbock 5 weeks ago, using WLP810 San Francisco lager yeast, and after three weeks of no activity, I have concluded that it is stuck at 1.032.  I would like to get it down another 4-6 points if I could.

Nine days ago, I brewed a 1.052 pilsner, and split the batch between WLP833 German Bock and WLP940 Mexican lager yeast.  Both are in a temperature controlled freezer set at 50°F.  The 833 is still chugging away, but the 940 is done.

I also have available a half gallon (growler full) of unfermented bock wort.  I grabbed it the day after I brewed, from the bit under the false bottom.  My thought is to boil up that half gallon of wort to ensure it is sanitized, adding a pint of water to knock the gravity down from 1.090 so it wouldn’t shock the yeast.  Then I would rack the pils, aerate the wort, then add it to the now empty primary with 940 yeast cake.  After a day, when it gets back to high krausen, I would add that to the stuck beer and swirl that in gently, in hopes to restart.

I am welcome to suggestions to improve my proposed plan.

there’s another thread somewhere (cant find it yet) where Mark talks about a yeast called “terminator” that I think he said would be appropriate for situations like this…i will keep looking.

EDIT: here it is…

Your fermentation is not stuck. Windsor cannot ferment maltotriose, which is why you have a high terminal gravity (i.e., Windsor is not the best yeast strain to use with beer styles above 10 to 11 Plato).  You have to deal with a double whammy at this point in that you cannot vigorously aerate a batch that is currently sitting at over 7% ABV.  My suggestion is to pitch 20 grams of the yeast strain that I like to refer to as the Terminator (a.k.a. K1V-1116 or Montpellier).  K1V-1116 (Lalvin K1-V1116) is one of the best kept secrets in high gravity brewing.  Unlike most wine yeast strains, K1V can ferment maltotriose.  K1V is an S. cerevisiae wine strain that is good to 18%.  It also emits a killer toxin that inhibits all other microflora in the fermentation; hence, the name Terminator.  Best of all, K1V is well known for its ability to restart a stalled or under attenuated high gravity fermentation.  K1V is POF- (phenolic off-flavor negative).

[chumley]

Thanks.  I am well aware of that strain, having used it 10 years ago to finish a stuck agave nectar mead (and an absolute fantastic job it did as well).  I thought I would start off with the lager yeast option, before proceeding with Option 2.  Believe me, that is being considered.

[wort-h.o.g]

@chumley

Thanks.  I am well aware of that strain, having used it 10 years ago to finish a stuck agave nectar mead (and an absolute fantastic job it did as well).  I thought I would start off with the lager yeast option, before proceeding with Option 2.  Believe me, that is being considered.

Yeah sure thing…always better to throw it out there.

I’d probably follow the same path you’re on.

[jonhughey_att.net (HoosierBrew)]

Chumley, sorry for the dumb question - I assume you roused and warmed ?

[chumley]

Yes, I have roused it several times, and it has been out of the fermentation chamber, sitting in the low 60s for a couple of weeks.

[brewinhard]

If your bock wort was never originally boiled and placed in the sanitized growler I wouldn’t be so positive that something hasn’t started working on the sugars in there already.  I know its a long shot, but even if you boil it to kill anything there may be some off-flavors in there that you could potentially add to your dopplebock that you don’t want. 
I would either rack some of the fermenting wort from your current lager directly into your dopplebock in hopes of kickstarting the fermentation or better yet, make a fresh 500 mL starter with an attenuative clean yeast strain and pitch it at high krausen into your wort.  IME, if you don’t gain the extra points from doing that then sometimes it is a recipe or process (mash temp, O2) issue.