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General Category => Yeast and Fermentation => Topic started by: bdgrfrisch on October 19, 2011, 02:47:25 am

Title: Dopplebock Fermentation
Post by: bdgrfrisch on October 19, 2011, 02:47:25 am
OK - I've always done session beers (everything was less than 1.060) so a "big" beer is new to me. I brewed up a 1.085 dopplebock. I pitched the slurry (WLP833) from a helles. I rinced the yeast slurry (1.5-2L) and pitched it into a 1L starter on brewday to get it active. That fully active starter was pitched into the beer later in the day (at 47F) and was fermenting the next morning. It fermented vigorously for a number of days (at 50F) and slowed down after 4-5 days and was showing no bubbling in the airlock at 10 days. I took a gravity reading on the 10th day and it was down to 1.028-30. There is still a lot of yeast in the beer - very cloudy just no signs of active fermentation.
This is about 65% attenuation and that yeast should do about 75% attenuation.
Again, this big of a beer is new to me. Assuming I keep it at 50F for another 10-15 days should I expect to see this continue to slowly drop down to about 1.020? I've always seen my 1.055 beers ferment out (actively) in 5-6 days and basically stop there (where they were expected to finish) so my experience says that this is done.
So, a little help for a newb in the deep water of these high gravity beers.
Title: Re: Dopplebock Fermentation
Post by: Malticulous on October 19, 2011, 02:56:27 am
Seams like a good time to warm it up to get it to attenuate a little better.
Title: Re: Dopplebock Fermentation
Post by: jamminbrew on October 19, 2011, 03:21:44 am
Airlock activity is no indicator of yeast activity.  The yeast can still be active. 
My big beers (I average 1.075-1.080) usually take 2-3 weeks to get down to final gravity. I get a flurry of activity for the first week, then it slows down, and takes a little while to finish. I wouldn't worry too much, but keep taking gravity readings.  I currently have a golden strong ale that started at 1.075, and after 17 days, is at 1.018, and still falling, albeit slowly. Did you use a yeast nutrient?
Title: Re: Dopplebock Fermentation
Post by: snowtiger87 on October 19, 2011, 05:05:56 pm
Nothing wrong with keeping it a few more days (a week even) at 50F to see if it drops more. Then let it warm up to 65 or so for a couple of days. This should accomplish 2 things - 1. finish it out, 2. diacetyl rest. Then slowly bring it back down to 50 F and rack to secondary.

I brewed a Doppelbock of similar gravity (1.084) and was not satisfied until it dropped below 1.020. I probably underpitched and had a heck of a time getting there but I finally did.
Title: Re: Dopplebock Fermentation
Post by: bdgrfrisch on October 20, 2011, 04:11:59 am
Thanks all.  I've raised the temp a bit and will let is keep going.  I did ad servomices for yeast nutriant and the starter also had some.  I'll check it weekly.  I'm shooting for 1.020 so we'll see what we get.  Then I suppose I should let it lager for a good long while - at least part of it. ;D