Doppelbock fermentation stuck?

[dirtydingus]

Single infusion mash, 60 min boil, recipe OG 1086 attained, 2.75 liter starter w/3 vials wlp833, fermented at *50 exactly, final gravity by recipe 1020, after week 1-1040, after week 2-1030, today is week 3-still 1030, Now what???

 

[thehaze]

We need more information on the recipe: what was the exact mash temperature and are you 100% sure it was actually correct? For me it seems your yeast pitch was low for a 10C fermentation temperature. I assume that you raised the temperature of the beer after two weeks, in order to force the yeast to finish and clean up after itself. If you did not, then you should.

You're now at 63% apparent attenuation. White Labs states a maximum of 76% apparent attenuation on this yeast. The range starts at just 70%. If you mashed high and had 10-20% specialty malts, then I would think it is done. But if you haven't done the d-rest, etc do it.

 

[VikeMan]

Two questions:

1) Grain bill, mash temp, mash length?
2) Hydrometer or refractometer?

 

[dirtydingus]

We need more information on the recipe: what was the exact mash temperature and are you 100% sure it was actually correct? For me it seems your yeast pitch was low for a 10C fermentation temperature. I assume that you raised the temperature of the beer after two weeks, in order to force the yeast to finish and clean up after itself. If you did not, then you should.

You're now at 63% apparent attenuation. White Labs states a maximum of 76% apparent attenuation on this yeast. The range starts at just 70%. If you mashed high and had 10-20% specialty malts, then I would think it is done. But if you haven't done the d-rest, etc do it.

5 mins after dough in *156, my mash tun is an orange 10 gal cooler. Yeast pitch was Mr. Malty reccomendation. I have not done the d-rest, but I will.

 

[dirtydingus]

Two questions:

1) Grain bill, mash temp, mash length?
2) Hydrometer or refractometer?

4#Pilsener, 14#Munich, 2#caramunich 60. Mash temp 156. length 60 mins. Hydrometer.

 

[VikeMan]

4#Pilsener, 14#Munich, 2#caramunich 60. Mash temp 156. length 60 mins. Hydrometer.

So, the Munich and Caramunich are not particularly highly fermentable. Mash temp ditto. And the yeast strain isn't a very strong attenuator. Putting all this into BrewCipher predicts an FG of 1.025 1.027. I suspect you're closer to your terminal gravity than you thought, if not already there.

Also, was this Munich II by any chance? In that case, the FG prediction becomes 1.029.

 

[thehaze]

Some yeast will kick off fermentation again, when warmed up, but this is a scenario that can happen, and will not neccessarily happen for you.

Your recipe and mash temperature suggests that you will not reach max. attenuation, but 1.030 seems a tad too high. But in the end, if gravity is stable, then it is done. Whatever the reasons.

 

[dirtydingus]

Some yeast will kick off fermentation again, when warmed up, but this is a scenario that can happen, and will not neccessarily happen for you.

Your recipe and mash temperature suggests that you will not reach max. attenuation, but 1.030 seems a tad too high. But in the end, if gravity is stable, then it is done. Whatever the reasons.

Thanx for the help

 

[dirtydingus]

Some yeast will kick off fermentation again, when warmed up, but this is a scenario that can happen, and will not neccessarily happen for you.

Your recipe and mash temperature suggests that you will not reach max. attenuation, but 1.030 seems a tad too high. But in the end, if gravity is stable, then it is done. Whatever the reasons.

Thanx for the help, I will raise temp to 165 for awhile.

 

[VikeMan]

Also, was this Munich II by any chance? In that case, the FG prediction becomes 1.029.

Scratch that. I botched the input. The FG prediction is 1.027, with either type of Munich. (Slightly different results for each, but both predictions round to 1.027.)

 

[thehaze]

Thanx for the help, I will raise temp to 165 for awhile.

I hope you mean 65F/18C and not 165F - raising the temperature might encourage the yeast to munch on some sugars - just keep it there a few days.

 

[JohnDBrewer]

You are doing a big lager. 4 weeks at lager temp (50-52) then raise it slowly for the D-rest (60-65) another week, not at 65 but getting up to that range. If its still stalled let it sit there longer. Usually this finish it off. Lagers take time.

Let us know.