Rack to secondary before/after reaching lager temp?

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njohnsoncs

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I'm brewing my first lager (a Pilsner) and I'm thinking of decreasing the temp down to lagering temp (~34 F) and *then* racking to a keg. I've heard people first rack and then decrease temp. It seems to make more sense to rack after reaching lagering temp since then some of the yeast will fall out and you avoid transferring as much as possible. This especially makes sense when you serve out of the same keg. What do people think? Any reason to not rack after reaching lagering temp?
 
The reason I rack to the keg and then reduce to lagering temp is that if you don't have a way to minimize oxygen intake into the fermenter, you could damage the beer. By doing this in a keg, you can lager under a slight amount of pressure.

- Transfer to keg
- Fill headspace of keg with 30 psi of CO2 (approx., doesn't HAVE to be 30)
- Purge keg 10-12 times
- Reduce CO2 to about 2-5 psi
- Proceed with lagering

I've even been doing this with cold crashing. As I don't have a solid way of avoiding oxygen during a cold crash, I've been doing all my cold crashes like the above.

You end up throwing out about the first 2 or 3 pints but that's about it.
 
The reason I rack to the keg and then reduce to lagering temp is that if you don't have a way to minimize oxygen intake into the fermenter, you could damage the beer. By doing this in a keg, you can lager under a slight amount of pressure.

- Transfer to keg
- Fill headspace of keg with 30 psi of CO2 (approx., doesn't HAVE to be 30)
- Purge keg 10-12 times
- Reduce CO2 to about 2-5 psi
- Proceed with lagering

I've even been doing this with cold crashing. As I don't have a solid way of avoiding oxygen during a cold crash, I've been doing all my cold crashes like the above.

You end up throwing out about the first 2 or 3 pints but that's about it.

Or you could spund (transfer to keg with a little remaining gravity (about 4 points)) and let it finish in the serving keg. It will naturally carbonate and the remaining yeast will consume any O2 you pick up in the transfer process.
Then once you are sure fermentation is finished, you cool to lager temps (slowly) and the yeast will settle out during lagering. A floating dip tube in the keg (like a CLearbeer system) will even eliminate the need to toss those first couple of pints.
 
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OP: Obviously it's too late for you to spund this batch, but remember, you want a little yeast in the lagering vessel, because (slowly while at lagering temps) they will clean up their fermentation byproducts and give you that clean lager we all love so much.
A lot of people think the benefits of lagering are just temperature causing stuff to settle out, but a fair portion of it is yeast continuing to interact with the beer during that time.

It is important to note also that you should NOT cold crash a lager. Cold crashing will shock the yeast and they will fall out of suspension and will not be able to do their cleanup, like removing residual diacetyl. Ideally you lower the temp to lager temps gradually so the yeast don't settle out right away.

Then again, there are fast lager people who will say all this is unnecessary. I disagree and lean on solid brewing science, but to each his own.
 
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Why would you have oxygen intake into the fermenter?

When you drop temp in a sealed fermentation vessel, like a carboy, the volume of liquid/air in the carboy condenses/shrinks and the vessel will pull in air from the outside, unless you can slowly feed it CO2 like you would in a keg with a regulator.

OP: A lot of people think the benefits of lagering are just temperature causing stuff to settle out, but a fair portion of it is yeast continuing to interact with the beer during that time.

It is important to note also that you should NOT cold crash a lager. Cold crashing will shock the yeast and they will fall out of suspension and will not be able to do their cleanup, like removing residual diacetyl. Ideally you lower the temp to lager temps gradually so the yeast don't settle out right away.

.

+1 to what @Cavpilot2000 said. The lagering phase isn't just clearing the beer. Flavors do change over that time and the beer becomes better. Like I said, I've only done one lager and the beer was ok 2 weeks into lagering but after weeks 4 & 5, it got fantastic.

Also piggybacking on @Cavpilot2000 comments, did you perform a diacetyl rest for this?
 
I personally don’t worry about oxygen as much as I should , But then again neither did people 150 years ago . I just solid bung my carboy, lower to laggering temps and let it sit . I know solid bunging a glass carboy is a nono but I do it ( don’t take my advise ) . I started doing it before I knew better and now I do it because hey what the heck.
 
OP: Obviously it's too late for you to spund this batch, but remember, you want a little yeast in the lagering vessel, because (slowly while at lagering temps) they will clean up their fermentation byproducts and give you that clean lager we all love so much.
A lot of people think the benefits of lagering are just temperature causing stuff to settle out, but a fair portion of it is yeast continuing to interact with the beer during that time.

It is important to note also that you should NOT cold crash a lager. Cold crashing will shock the yeast and they will fall out of suspension and will not be able to do their cleanup, like removing residual diacetyl. Ideally you lower the temp to lager temps gradually so the yeast don't settle out right away.

Then again, there are fast lager people who will say all this is unnecessary. I disagree and lean on solid brewing science, but to each his own.

I did a diacetly rest for about 5 days and didn't test any significant diacetly after. It's been fermenting for about 3 weeks so it's reached FG and there's no diacetly. My understanding is that the yeast go dormant (even if I kept at high temp) so are they even active when I lower the temp to lager? If not, then why not rack after they fall out?

When you drop temp in a sealed fermentation vessel, like a carboy, the volume of liquid/air in the carboy condenses/shrinks and the vessel will pull in air from the outside, unless you can slowly feed it CO2 like you would in a keg with a regulator.

Isn't this the point of an airlock? To keep out oxygen and other stuff? If I decrease the temp, how is oxygen getting in through the airlock? Also, don't people cold crash in the primary fermenter? If so, why do they not have to worry about oxygen getting in?
 
I did a diacetly rest for about 5 days and didn't test any significant diacetly after. It's been fermenting for about 3 weeks so it's reached FG and there's no diacetly. My understanding is that the yeast go dormant (even if I kept at high temp) so are they even active when I lower the temp to lager? If not, then why not rack after they fall out?



Isn't this the point of an airlock? To keep out oxygen and other stuff? If I decrease the temp, how is oxygen getting in through the airlock? Also, don't people cold crash in the primary fermenter? If so, why do they not have to worry about oxygen getting in?

No, lager yeast do not go completely dormant at lagering temps, at least not if you gradually lower the temp like you should (cold crashing will shock them into dormancy, which is why it is not an ideal practice if you want the real benefits of lagering). So yes, they are still somewhat active, though at a very reduced rate, at lagering temps (again, as long as you didn't shock them), which is why the benefits they bring to lagering (like cleaning up sulfur and other fermentation byproducts like diacetyl, which is probably still present, even if below perceptible levels) take a long time. THey are slow and sluggish, but still active to a degree.

It is a common misconception that lager yeast go completely dormant. even at 0*C. Below 0*C they may go dormant (see Kunze).

Re: Airlock: No, the airlock does not keep out oxygen. It is primarily to keep out airborne contaminants like wild yeasts and bacteria.
What Rob2010SS is referring to is called suckback. The airlock pushes bubbles out when there is CO2 being produced in the fermenter. When those bubbles are no longer coming out, if yo were to chill the beer, its volume shrinks. That reduction in volume creates a vacuum in the headspace of the fermenter and air (as well as some of the liquid in the airlock if you are using a 3-piece) will be sucked into the fermenter by that vacuum.

And even if there were no temperature change, the water in the airlock contains dissolved oxygen and it is constantly releasing and reabsorbing oxygen from the air. So, it effectively allows oxygen to pass into the fermenter. It's at a slow rate, but it still happens. Thus, airlocks do not (nor are they meant to) keep oxygen out of the fermenter.
 
Isn't this the point of an airlock? To keep out oxygen and other stuff? If I decrease the temp, how is oxygen getting in through the airlock? Also, don't people cold crash in the primary fermenter? If so, why do they not have to worry about oxygen getting in?

As @Cavpilot2000 said, airlocks do not keep out oxygen. If you want to see it in action, put an "S" type airlock on your carboy as you're cold crashing. Watch what happens to the bubbles. The liquid will all move to the other side of the airlock because the carboy is sucking in air.
 
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