Diacetyl rest and lagering in kegs

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MadHopper

MadHopper

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Couple of questions about an Oktoberfest lager I brewed a couple of weeks ago. The fermentation was at 40F and seemed to have stopped (for various reasons, I was not able to take gravity readings).

I started the diacetyl rest on Monday - raised temperature to 62F. This morning I noticed quite an active fermentation going on - 2/3 bubbles per minutes in the airlock. Is this normal? I have brewed a lager only once before and don't remember so much fermentation during the d-rest period (or perhaps I am just forgetting). There is also a bit of an off-smell coming from the airlock - can't really pinpoint it - but there is definitely an odor in addition to the sweet smell of the beer. Any ideas on what this could be?
(I used the Wyeast Oktoberfest Lager blend)

Second, I was thinking of transferring the beer directly to the keg for lagering. I have searched and found a few threads where it says this will be fine. However, I was wondering if it is better to cold crash the beer in the primary first (bring down temperature gradually to ~35F) and then transfer to the keg or transfer first and then cold crash/lager in the keg? If I cold crash in the primary, the temperature of the beer will rise anyway during racking, hence I was thinking of the rack then cold crash route.
 
I did as you described above for my oktoberfest that I brewed in march, fermentation increased a bit during my d-rest, but not crazy. I brought the temp down to 33° over several days, then racked to a keg. after several weeks in the kegerator I transferred to another keg to get it off any sediment that precipitated out and it continues to lager til sept. thus far I have sampled it a few times and everything tastes great, I just hope I can stay out of it til sept!
 
I like to rack off of the yeast cake right after the diacetyl rest, when the beer reaches FG. Then you can lower the temperature for the lagering phase. I don't see an advantage to raising the temperature for a diacetyl rest, the lowering it to cold crash while the beer is still on the yeast cake. I suppose more yeast would fall out, but it's not likely to be much more.
 
YooperBrew said:
I like to rack off of the yeast cake right after the diacetyl rest, when the beer reaches FG. Then you can lower the temperature for the lagering phase. I don't see an advantage to raising the temperature for a diacetyl rest, the lowering it to cold crash while the beer is still on the yeast cake. I suppose more yeast would fall out, but it's not likely to be much more.
Click to expand...

Yeah, well what do you know little miss 24,000 posts! :D
I kid, I kid! It is probably best to get it off the cake after the d-rest, but I had no remaining carboys so I crashed it and kegged with no ill effect that I have noted.
I could bottle one up and ship it to you for taste testing if you would like!
 
azscoob said:
I could bottle one up and ship it to you for taste testing if you would like!
Click to expand...

I'm always up for doing quality control for my friends. :D

Truly, it probably doesn't matter that much, but for lagers I'm usually getting the beer off of the yeast cake ASAP. Not too early, but as soon as primary is finished and the diacetyl rest (if needed) is finished. I'm sure a few days won't matter, and I'm thinking the temperature changes wouldn't be that severe, but I don't like changing temperatures more than I have to. I realize that you can rack the beer while still cold, but it seems like it would warm up a bit during the racking procedure, then be chilled again in the kegerator. Again, probably not a big deal at all but something that I've always prevented.
 
MadHopper said:
Couple of questions about an Oktoberfest lager I brewed a couple of weeks ago. The fermentation was at 40F and seemed to have stopped (for various reasons, I was not able to take gravity readings).

I started the diacetyl rest on Monday - raised temperature to 62F. This morning I noticed quite an active fermentation going on - 2/3 bubbles per minutes in the airlock. Is this normal? I have brewed a lager only once before and don't remember so much fermentation during the d-rest period (or perhaps I am just forgetting). There is also a bit of an off-smell coming from the airlock - can't really pinpoint it - but there is definitely an odor in addition to the sweet smell of the beer. Any ideas on what this could be?
(I used the Wyeast Oktoberfest Lager blend)

Second, I was thinking of transferring the beer directly to the keg for lagering. I have searched and found a few threads where it says this will be fine. However, I was wondering if it is better to cold crash the beer in the primary first (bring down temperature gradually to ~35F) and then transfer to the keg or transfer first and then cold crash/lager in the keg? If I cold crash in the primary, the temperature of the beer will rise anyway during racking, hence I was thinking of the rack then cold crash route.
Click to expand...


Sulfur smell ? As I recall Oktoberfest lager that I did reeked of sulfur for awhile. Increased activity from warming temps could be fermentation finishing or if it already did finish then CO2 escaping along with Sulfur. I always cold crash my primary first and then transfer to kegs so that I leave more of the yeast/trub behind. Just make sure you take your Hydro readings.
 
MadHopper, it looks like your primary fermentation temperature was too cold at 40°F. 42°F is pretty much the bottom end for even the most hardy lager yeasts. Primary fermentation probably stalled out at 40°F and started up again when you raised the temperature, hence the odor.
 
menschmaschine said:
MadHopper, it looks like your primary fermentation temperature was too cold at 40°F. 42°F is pretty much the bottom end for even the most hardy lager yeasts. Primary fermentation probably stalled out at 40°F and started up again when you raised the temperature, hence the odor.
Click to expand...

That's a good point! I saw the 40 degrees, but assumed it was a type and 50 degrees was meant. Menschmachine is correct- if it was fermented at 40 degrees, it probably didn't ferment out and started up when the temperature got warmer.

Lager yeast tend to have a sulfur odor, but fermented too warm it's worse.
 
Thanks to everyone for their input. I am sorry - that is a typo - I brewed near 50F, the lower end of the recommended range for the yeast.

However, I had a look at it today, and fermentation is still going on and the sulfur smell is getting stronger. So, I am not really sure what's going on. My yeast activity started a bit late (~30hours) since I forgot to make a starter for this. I am worried if there is some possible bacterial contamination. As such, visually I don't see any indications.

I assume I should wait till this fermentation stops before beginning the lagering process?
 
MadHopper said:
Thanks to everyone for their input. I am sorry - that is a typo - I brewed near 50F, the lower end of the recommended range for the yeast.

However, I had a look at it today, and fermentation is still going on and the sulfur smell is getting stronger. So, I am not really sure what's going on. My yeast activity started a bit late (~30hours) since I forgot to make a starter for this. I am worried if there is some possible bacterial contamination. As such, visually I don't see any indications.

I assume I should wait till this fermentation stops before beginning the lagering process?
Click to expand...

Yes, you want to wait until fermentation is over, and a diacetyl rest is done before racking and lagering. A hydrometer would be very helpful in all of this.
 
MadHopper said:
Thanks to everyone for their input. I am sorry - that is a typo - I brewed near 50F, the lower end of the recommended range for the yeast.

However, I had a look at it today, and fermentation is still going on and the sulfur smell is getting stronger. So, I am not really sure what's going on. My yeast activity started a bit late (~30hours) since I forgot to make a starter for this. I am worried if there is some possible bacterial contamination. As such, visually I don't see any indications.

I assume I should wait till this fermentation stops before beginning the lagering process?
Click to expand...

Yes, you want to wait until fermentation is over, and a diacetyl rest is done before racking and lagering. A hydrometer would be very helpful in all of this.
 
I am in the same boat. almost exactly, lol! now i want my ferm fridge for another batch and put my two kegs in a small freezer for lagering. When I rack to the kegs to lager, what amount of CO2 do i put on them...just head psi or 12 lbs as normal?
 
FenoMeno said:
I am in the same boat. almost exactly, lol! now i want my ferm fridge for another batch and put my two kegs in a small freezer for lagering. When I rack to the kegs to lager, what amount of CO2 do i put on them...just head psi or 12 lbs as normal?
Click to expand...

I woud also like to know what others procedure is for lagering in the keg. I recently did my FIRST lager and didn't put it under any pressure because I heard it would kill the yeast. Now after a month of lagering I put it under Co2, poured a pint for the beer gods and drank the second one and it has a very sour taste. I have left it alone for the past couple days thinking it might settle out but haven't tried it again yet. I am afraid it might have gotten infected from the lid not being sealed by Co2.
 
Trev4956 said:
I woud also like to know what others procedure is for lagering in the keg. I recently did my FIRST lager and didn't put it under any pressure because I heard it would kill the yeast. Now after a month of lagering I put it under Co2, poured a pint for the beer gods and drank the second one and it has a very sour taste. I have left it alone for the past couple days thinking it might settle out but haven't tried it again yet. I am afraid it might have gotten infected from the lid not being sealed by Co2.
Click to expand...

If pressure killed yeast, natural carbonation and bottle bombs would be impossible, no?

"Very sour" sounds like an infection, which I would fully expect if I had left the keg unsealed. Carbonating during the lagering process is typical and I believe historical.
 

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