Fermenting a doppelbock

[BlueHouseBrewhaus]

I currently have a high gravity doppelbock in the fermenter.

Munich II 60%
German Pils 20%
Vienna 10%
Caramunich 6%
Carafa III 2%
Melanoiden 2%

Safelager 34/70 - 4 packets

I decided to pass on a decoction (hence, the melanoiden). With the high gravity and so much Munich, I did a temperature mash to hopefully improve efficiency and threw in the pils and Vienna to help with conversion. Started at 140F then ramped to 155F over 45 min. Total mash 75 min then mash out.

The "improve efficiency" part worked a little too well. I ended with OG 1.100 (planned 1.092). Cooled to pitching temp and fermented at 54F.

I checked it after the first week and it was down to 1.032 so I warmed it to low 60's to finish it. It has been another week and it's sitting at 1.030. I've roused, added amylase enzyme and upped the temp to mid-60's.

So I'm sitting at 70% AA, which isn't awful but it's still a bit too sweet even for a doppelbock. The 4 packs of 34/70 should have been fine even at the higher gravity and I treated the yeast very nice - rehydrated and slowly cooled to pitching temp. I oxygenated (pure O2) before pitching and again 15 hours after pitching.

This is my first Doppelbock (brewing for 6 years) and research seems to show FG can easily be in the mid-1020s. I haven't repitched since in my experience it has rarely helped. BeerSmith shows Weyermann Munich II as 25 lintner for diastatic power. That may be my issue even with the pils and Vienna.

So, after that long post ..... any ideas or am I done?

 

[specharka]

I think you’re pushing the alcohol tolerance of W-34/70. Even at 1.030 you’re looking at a 10% lager with a decent amount of headroom. If you are still concerned with tasting too cloying, you could try jump starting it with a satchet of US-05 or Nottingham, both of which ferment reasonably dry and clean. Warm it to the mid 60s and pitch more yeast if you’re feeling lucky.

As an aside, you still underpitched even with 4 satchets. Assuming 100% viability and 5 gallon batch, you are still only achieving 0.98 M cells / mL-P, far from the recommendation of 1.5-2.0 (for lagers).

 

[Upthewazzu]

34/70 tends to under-attenuate in the 1st generation, and it looks like you underpitched as well.

 

[BlueHouseBrewhaus]

Unless I missed something, the pitch rate should have been fine. Two separate pitch rate calculators (YeastCalc and BeerSmith) both called for 680b +/- cells. At 200b/pack, that should be more than enough. The Fermentis data sheet also calls for 15-22g (1.5-2 packs) for 5 gal so doubling it to four 11.5g packs for the higher gravity also seems reasonable.

The alcohol level is a different matter. That may be the problem. Some sources say 34/70 is good to 9% and others say 10.5%. The combination of high alcohol and 1st generation (thanks, wazzu) could be the issue. I will give it a shot of US-05 and see what happens. Thanks guys.

 

[Duffman870727]

Re-pitching is hardly ever an ideal solution... All that's left for the yeast to eat now are the complex sugars, plus you're throwing them into a highly stressful environment and adding additional oxygen now is not a good practice. If you are going to re-pitch, get the US-05 rocking in a 0.5L starter, add at high krausen, and also feed some plain candi sugar into the doppelbock (dissolved in water, about the amount you'd add to bottle condition the batch) so your yeast has some simple sugar to dig into before it tackles the maltose.

Option A: Chalk it up to a learning experience, dilute down to your target pre-boil OG if your efficiency was higher than expected (or post boil with hot water before chilling the wort). Keg it now as a lagered barleywine, consider dry hopping to balance the sweetness with polyphenols and tannis from the hops.

Option B: Add some Brett and sit on it for 3-6 months before packaging. It won't be what you were going for, but it'll be a funky and interesting beer that will get dried out by the Brett that can actually eat the complex sugars remaining in the beer at this point.

 

[BlueHouseBrewhaus]

Well, I pitched a pack of US-05 this morning with a few ounces of sugar. As I mentioned, I don't typically find repitching to be very useful. But at this point, I've got nothing to lose. So I'll give it another week and we'll see what happens.

 

[Comfort_Zone]

For a giant big lager like that I'd use S-189. That's the perfect yeast for that. At this point though, you might be able to get away with pitching a high attenuating ale yeast.

 

[Tulsahomebrewer]

Just found this post, how did it finally come out? I have a small batch Doppelbock in the fermenter for 10 days now. Pitched S04. OG was at 1.079 and yesterday’s reading showed 1.021 which is almost 74% attenuation. Should I let it ferment for another week, or is it time to prime and bottle?

 

[RM-MN]

Just found this post, how did it finally come out? I have a small batch Doppelbock in the fermenter for 10 days now. Pitched S04. OG was at 1.079 and yesterday’s reading showed 1.021 which is almost 74% attenuation. Should I let it ferment for another week, or is it time to prime and bottle?

The fermentation was probably done a few days ago but leaving the beer in the fermenter will allow more yeast to settle out and the beer to start maturing. Being a Doppelbock it will need some time to mature anyway and why bottle all the excess yeast. Another week or even a month more won't hurt the beer and will leave you with less sediment in the bottles.

 

[BrewMan13]

I agree, 10 days is a ridiculously short fermentation time for a d-bock, even when using ale yeast. I did one with a similar OG as the OP and fermented it for a month, before racking and lagering (still in this phase). Also like OP, I got only 70% AA. So while it may be done at 74%, you definitely want to let it sit another week or 2 before doing anything with it.

 

[Tulsahomebrewer]

Thanks. I wonder if I should leave it at 65-68F as it is now. Or can I move it into a fridge to cold crash for 10 days?

 

[BlueHouseBrewhaus]

Finally checking back in. My d-bock finished at 1.028. The US-05 helped a little. It was still higher than I wanted so it's a bit on the sweet side but not annoyingly so. I gave it 2 weeks in the mid 60s. A week of that was with the US-05. I bulk lagered for a month and then bottled with CBC-1 yeast in hopes of maybe knocking another point or two off and to be sure it would carb OK. I deliberately undershot the CO2 volumes a little to allow for that. It seems to have worked OK. After 6 months in the bottle, it has dried out a little and the carb level is just right. Still sweeter than I would have liked but enjoyable nonetheless. At a final 72% attenuation, it's still below the supposed range for 34/70 but it sounds like that's common for this yeast. I may try something else next time.

 

[BrewMan13]

Well, what a coincidence, mine went exactly from 1.100 to 1.028 as well. Except when I plug that into to a calculator, it indicates that's only 70% AA. I did use a different yeast, WL833. Anyway, I attributed my low AA to targeting a lower OG for the yeast starter (accidentally used 2lbs more malt than I intended; also, did a double decoction which increased my efficiency), and not having figured out how to properly use my O2 wand yet. Then again, it's in the range for the yeast at least, so not too disappointed. Not drinking it yet so yet to taste the final result.