Doppelbock fermentation and lagering question!

Question

Iv'e got a Doppelbock 1.090 brewed 7/19. Pitched the Whit Labs "X" at 60 deg. Placed the carboy in the fridge (first time trying a lager fermentation). Two days later the beer was at 44-46(thats the highest temp I can get my fridge), fermentation was ok (again I'm used to ale temp fermentation), krausen was in between an inch and a half of an inch. I currently use a "blow-off" and the air bubble was always below the water level but never at the bottom of the tube. On the 31st (12 days later) my gravity was 1.050 so I decided to warm up the sluggish(?) fermentation by taking it out and wrapping it in a blanket (slow warm-up). Well we had a little heat wave here in Washington and according to the stick-on thermometer temp is now at the last square 76 deg. (currently 1.030)

So my question is what can I expect, and what can I do? fermentation was more then 50% complete so at this point, so am I reducing diacetyls quicker at higher temp or did I not take it far enough? I'm assuming putting it back in the fridge isn't going to do me any good.

I am also looking for advice on lager conditioning as well, this will be one of my wedding beers so I really would like it to be more then good (wedding 9/29)

Thanks for the help guys!! sorry about the length of this question

Answer 1

Well first of all, you can't really turn around a 1.090 Lager in two months time (7/19 - 9/29). Its going to need 3 months of lagering minimum AFTER fermentation is totally done. So if you really want beer that's "more than good" for your wedding, then you need to brew a backup Ale right now that has a short maturation period. (I suggest a wheat beer, like a Hefeweizen or a Blue Moon clone. Seriously, people love those beers. I would not expect a 1.090 Doppelbock to go over well at a wedding at all, unless the entire group are beer snobs.)

Secondly, lager fermentations are often much slower than ales. You did not need to warm that beer up by much (I shoot for around 52F), and it probably would have been perfectly fine to ferment a while longer at 46F. A diactyl rest at elevated temps should have been started when that beer was around 1.030, not 1.050, so the impact of this is that you will get a bit of extra flavor from esters thrown by the yeast at 76F. If you try to drop the temp now, you run the risk of the lager yeast going to sleep prematurely, before fermentation and cleanup is done. (I'm not sure how sensitive your lager strain is to temp drops. Lagers handle it better than ales but I wouldnt drop the temp by more than 5-8 degrees suddenly.)

So, (1) don't drop the temp now because it will do more harm than good, (2) the beer probably won't be ideal, as it has fermented too much at high temps, and (3) you really need 3-4 months lagering for a Bock that big, for future reference.