Ever since I built a fermentation chamber out of a mini fridge last fall, I’ve been brewing a lot of lagers. I usually use Wyeast 2206 or White Labs WLP830 to ferment and I typically ferment between 46-50 degrees. I’ve been extremely pleased with the lagers I’ve brewed over the past few months, but I’ve been surprised how much less fermentation activity is evident in lager fermentations as compared to that of ales. This is probably to be expected given the lower fermentation temperatures, i.e., the yeast don’t groove as hard in the cold.
Right now, I’m fermenting a 1.069 Maibock with WLP820. According to Mr. Malty, I pitched an adequate slurry from a previous batch (schwarzbier) and I aerated the crap out of it with my mix-stir. Pitched at 44 and it seems to be happily fermenting between 46-48 now. Despite visible signs of fermentation (as seen through the wall of the glass carboy), however, the airlock is only bubbling once every 10 seconds or so. At most, the airlock only bubbles at a rate of once per every 5-7 seconds for my lagers. Is this pretty normal for lager fermentations? Like I said, I’ve been extremely pleased with my lagers thus far (and that’s what really matters), but I’m just curious about others’ experiences.
My lagers are very docile compared to my ales so this is pretty normal. I have a rauchbier that’s been chugging along at 3 or 4 bubbles per minute for 2 weeks. It finally got from 1.072 to 1.022 in 2 weeks so I bumped the temp to 62 for a diacetyl rest.
My German Pils type beers are done in 5 to 6 days, of course a rest is now done at about 75% the way down, which helps finish it a little faster. Doppelbocks are done in 7-8 days. Both get extra time on the yeast to clean up more.
Lots of yeast, lots of O2, some zinc in the boil, and a temp control on the conical all help.
Leos AKA “Thirsty Monk” had posted a fermentation chart from his trip to the Czeck Rep. It was pretty much done in 120 hours, which is 5 days the way I see it.
I typically pitch my lagers in the mid-40’s and let them warm up to 50. It takes about two days before I see active fermentation (krausen and air-lock activity). My last Ofest finished (active fermentation) in about 7 days. After fermentation I slowly warm up the beer to about 60 degrees for a few days. I then cold crash the fermenter for several days and keg.
Ok, it sounds like my experience is pretty much like all of yoos guys’. The maibock has picked up a little steam in the last day or so. Going strong at 47.
My lagers usually finish or get close to finishing within 10-14 days. Then I do a 48-72 hour diacetyl rest, after which I gradually cold crash the beer to lager temps over the course of a week.
My lagers fermenting process is similar to yours. Except I fill the 6gal carboys with wort almost all the way to the top, so when fermentation hits it can kick-out the ‘braun hefe’. I surely can’t do that with ale fermenting.
I’m curious. Are you going by your temp inside the cooler? Or the temp on your fermometer? I ask because I have to set my temperature control lower than the target temp (e.g., 44 to keep my fermometer reading between 51-54).
So, your fermometer is at 46 or 47, and your ambient is around 42. Wow, I didn’t know the yeast would respond well that cold. Most of the White Labs strain recommendations are in the low 50’s I think, but I see Wyeast 2206 is listed at 46-58. There must be an advantage you see in fermenting below 50. Do you get better flavor that way?
Interesting points. Having just inaugurated the fermenteezers I also noticed that in a small enclosed space the heat contribution of the buckets is significant…like 4+ degrees. So, indeed, initially set the controller lower than what you want…
I just checked out the thermowells, they look pretty cool. Do you prefer the stopper or hood version? Assuming they work better with digital controllers, should I replace my analog controller to use one?
Interesting that most of you are finding such large temp diffs between ambient and internal fermentation. On ales, I agree, I find such differences of four degrees or more. But on the two lagers I monitored this winter, the difference was only two or three degrees, max. This was with two digital thermometers that were calibrated to a standard at the fermentation temp, of 48 - 52 depending.
This was using a plastic six gallon bucket in a fridge, controlled by a JC A419.
Edit: Looked back through my notes, and it was not ambient air temperature that I was measuring. Rather, the temp probe was taped to the bucket exterior and covered with a double layer of bubble wrap. So that probe measured only 2 or 3 degrees difference from the exterior ferment temperature. I generally do not measure the ambient air temp inside the fridge as it fluctuates so much. I keep the JC probe taped to the side and under bubble wrap now.