Lagers - Cold Conditioning Technique

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I have a continental lager that I'm brewing for a function. I don't brew many lagers and keen to see what others do for cold conditioning.

I have done a search on this and haven't found any topics that cover this.

I'm currently at a diacytl rest and about to lower the temperature for the lagering phase.

The brew is AG with 90% pilsner malt and 10% rice flakes. Cold pitched with S-189 (2 packs) and fermented at 12 degC with rest at 15-16 degC.

I have read that you should lower the temp by 1-2 degC a day to lager temp to avoid shocking the yeast and having it drop out. In the past I have cold crashed and then lagered.

What do most people do? And can they tell the difference between the two methods?
What duration of cold conditioning (2degC) do they get good results with this type of beer?

Appreciate any comments and advice.

 

[Bribie G]

After a diacetyl rest I simply crank mine down to -1 and leave for a few weeks. I've been told that this temperature is the most effective and that anything over zero degrees takes far longer - most of the commercials lager at that temp. Fortunately I have a new Kegmate style fermenting fridge that will get down to those temps.

One thing you could do to get your fridge as cold as possible is to make a "baffle" out of this stuff from Clark Rubber, and place it between the lagering vessel and the fridge door, and turn the fridge control to coldest, and get an accurate fridge thermometer and see how you go.

 

[[email protected]]

BG I knew you would have a view. Thanks. This is what I have done previously.

I was hoping that someone could give a view on the slow lowering of temperature. Florian? I know he does a few lagers.

 

[dr K]

abc
you ask an excellent question!
for my answer first some background, lagering is not just holding a beer cold for some time, it is allowing continual fermentation at lower and lower temperatures to avoid yeast shock given the small volumes of home brew fermentors this is difficult.
this first slow stage in lagering is to finish fermentation, clean up the diacetyl and acetaldehyde really.
the answer is the narziss/diacetyl rest which essentially speeds up maturation and substitutes for the first stage of lagering
in a commercial environment it gets beer out quicker and in a home environment it substitutes.
so, skip the controlled temp drop after diacetyl rest and enjoy your beer.

K

 

[[email protected]]

Dr K I think your statement about the fact that lagering is not just cold conditioning but a part of the fermentation stage is exactly why I asked the question.

So in a commercial environment they do a d rest and then cold crash to lager?

Im interested that as a homebrewer the d rest and cold crash substitutes. I have been reading a bit on lagers (Greg Noonan, Gordon Strong) and they both talk about a d rest and then a slow ramp down to prepare for the cold stage.

Is it just one of those views adopted by American homebrewers like you must chill immediately.

 

[gunbrew]

This white labs pdf is worth a look.

www.whitelabs.com/beer/Diacetyl_Time_Line.pdf

Cheers.

 

[kevin_smevin]

Dr K is spot on. Traditionally the temp was dropped slowly so the yeast would remain active. If you do a D rest and are happy that your flavours are clean etc then you dont really need to do this. You do have to be careful about how quickley the temperature drops. I cant remember off the top of my head what the exact rate of temp drop is (it's in Jamil and Chris Whites yeast book), but if you crash the temp too quick you shock your yeast. This leads them to express heat shock proteins (not sure what effect this has) but also makes them throw out any esters etc that they may be harboring inside leaving your beer not so clean and crisp as you would have hoped.

 

[[email protected]]

I had a listen to the brewstrong podcast with Jamil and John Palmer today.

Their view is that if it is completely fermented properly (narziss/diacetyl rest) then straight cold crash is fine. The lagering period is more for a clarification and reduction in polyphenols etc.

It appears the text recommendations still hang onto some of the older methods and are not necessary.

Thanks for everyones' views. I will just cold crash, lager and fine with gelatin.

 

[felon]

Here is a world of info.

http://braukaiser.com/wiki/index.php?title=Fermenting_Lagers

 

[dr K]

Lets look at cold crash
I ferment in an old but working fridge.
At completion of fermentation, which may include a Diacetyl rest I turn the temp controller down to 0C.
The beer in the fermentors is not going to rapidly reach this temp, I guess anything from 6 to 9 hours, though I should, can and will test it for my fridge as I have a handy little $12 USB temperature data logger which emails me the results (I just have not taken it past testing).

K

 

[Thirsty Boy]

I think DrK is on the money here - if you were capable of knocking the temp of your fermenter down from D rest to -1 in a few hours... then I'd say that you might want to slow that down a bit. But really, its probably going to take the best part of 24hrs to get there anyway in most domestic fridges. I think the risk factor is pretty small.

 

[[email protected]]

Thanks all. I will just wind the temp down on the controller and then lager in my keg fridge.

 

[parrja]

$12 USB temperature data logger

Where did you get that? Everytime I look into hooking up my PC to my brew fridge it all gets too expensive.