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Cold Crashing

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amcqueen

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Hi Guys,

Ive got a lager brewing in my temp controlled fridge and its a week since it started fermenting at 11c. I was looking into cold crashing, and have seen a lot of differing points of view and am a bit confused....

I have never transferred to a secondary (and dont really want to with this brew) and wanted to know if I do cold crash into the primary, then at what temp? and for how long? and also would 2c suffice? What does everyone recommend for a good temp?

Cheers
 

manticle

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Don't put it in the cold until it's finished fermenting and sat for a bit longer at ferment temps or higher. One week, two weeks, doesn't matter. Stable gravity over a few days, around where you would expect it to be is finished.

Don't worry about transfer to secondary, down to 2 deg will be fine, 1 week or more if you have the patience, time and space.
 

Wolfy

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As manticle said (didn't we just do this in another thread?) leave it to fully ferment out before chilling it, I'd even consider letting it warm up for a d-reset for a couple of days as fermentation is finishing.
Then you essentially want it as cold as you can get (without freezing) for as long as you can keep it there (within reason). So 2degC is fine, and you want to lager it for at least 2-4 weeks.
In regard to transferring it to a secondary container, unless you plan to lager it for more than a month or so, I'd suggest you just do it all in the primary.
 

amcqueen

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LOL thanks, I think that thread might be mine as well

One more question... Ive read about suck-back of water in the airlock into the wort when the temp is dropped, which is not ideal, do you recommend removing the airlock when just about to do this and cover with something? Or just leave the airlock in?
 

Wolfy

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The only suck-back issues I had with airlocks (when I used them before I became an enlightened cling-wraping-brewer) was from squeezing/lifting the fermemtor without removing the airlock first. However by the time you are lagering your beer the fermentation is essentially finished, so there is little-to-no discharge of CO2 so anything to cover the airlock hole - sticky tape, a bottle cap, whatever - will keep the bad stuff out, which is all that you need to ensure.
 

warra48

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Don't even think about dropping the temperature if it's only a week into fermentation at 11C. It won't be done as yet.
I'd leave it for about 3 weeks to let it do it's thing. Then do a diacetyl rest if you feel you need one, but I never bother.
Then drop the temperature down for lagering. Just do it all in primary.

My last lager was 3 weeks at 9.5C, then dropped to 2.5C for 7 weeks, all in primary, no D rest. It's one of the cleanest clearest beers I've ever made.
 

sgw86

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As above I complete the Cold Crash for all my brews.

I will leave my brews for a minimum of 14 days (longer if required for Lagers) and then once I have stable readings over two days I chill it down to 1C (in the primary) and leave it for 7 days (5 if I need to get it kegged quicker).

My approach above produces very nice brews and the cold crashing makes a big difference for me.
 

donburke

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As above I complete the Cold Crash for all my brews.

I will leave my brews for a minimum of 14 days (longer if required for Lagers) and then once I have stable readings over two days I chill it down to 1C (in the primary) and leave it for 7 days (5 if I need to get it kegged quicker).

My approach above produces very nice brews and the cold crashing makes a big difference for me.
contrary to all the advice above, you can in fact start dropping the temperature prior to completion of fermentation

quote from braukaiser.com

The conventional fermentation in a German lager breweryThe majority of the information given in this section is taken from a German brewing text book "Abriss der Bierbrauerei" (Overview of beer brewing) by Ludwig Narziss, one of Germany's leading teachers and experts on brewing.

After the whirlpool the wort is cooled to close to 32 F (0 C) to maximize the cold break. It is then warmed up to pitching temperature which can be between 41 F (5 C) and 46 F (8 C). The majority of the cold break (~ 60%) is removed through either sedimentation tanks, flotation tanks, centrifuges or filtration. Filtration is the only means of complete cold break removal the other methods remove only about 2/3 of it. Once the cold break is removed the wort is aerated with sterile air to achieve a wort oxygen content of 8-10 ppm (mg/l). In case of cold break removal through flotation, the aeration of the wort is achieved during the flotation process.

Yeast is pitched at about 500 ml thick yeast slurry per 100 l 12 P (1.048 SG) wort (this equals about 100ml or 3oz yeast slurry per 5 gal). Once the yeast is well distributed this equals about 15 x 10[sup]6[/sup] cells per ml wort. When it comes to pitching and primary fermentation temperatures cold and warm lager fermentation exists. The cold fermentation uses a pitching temperature of 41 *F (5 *C) and a maximum fermentation temperature of 48 *F (9 *C) and the warm fermentation uses a pitching temperature of 46 *F (8 *C) and a maximum fermentation temperature of 50 - 54 *F (10 - 12 *C). This should however not be confused with warm vs. cold pitching. There is no warm pitching in commercial German lager fermentation.

Once the yeast is pitched it takes about 24 hours for the low Kraeusen to develop. High Kraeusen starts on the 3rd day, when the maximum temperature is reached and lasts until the 5th day. At this time yeast growth slows down and the yeast starts to flocculate. This is when the beer is slowly cooled at a rate of 0.5 - 0.7 C in order to avoid shocking the yeast. At this time the primary fermentation is considered done, but the beer has only attenuated to about 40% - 60%.

A few days later, when the beer is racked to the secondary/lagering tanks it has a temperature of about 39 - 41 *F (3.5 - 5 *C). The remaining fermentable extract is 1.2 - 1.4 % by weight (about 5 - 6 gravity points). Many breweries mix beer from different batches in the lagering tanks to compensate for fluctuations in color, bitterness, attenuation and other parameters. The addition to that 20-50% beer fermented with low flocculating yeast is beneficial for achieving a higher attenuation since this yeast will work longer than better flocculating strains of yeast.

During the secondary fermentation (a.k.a lagering) the tanks are closed and the pressure build-up is controlled by a pressure sensitive bleeder valve. This system, called Spundungsapparat, ensures the proper carbonation of the beer during lagering. The German Purity Law prohibits the use of non-fermentation CO2 for beer carbonization. It is also more economical for a brewery to use the CO2 produced during fermentation.

Key for a good lagering is control of the yeast contents and temperature profile such that the fermentation slowly continues during the whole time the beer is lagered. Only this allows for the processes to happen that are commonly referred to as maturation: reduction of diacetyl, acedealdehyde, higher alcohols etc. The lagering takes between 4 weeks and 6 months. At the end of lagering the beer has the desired attenuation, which is generally a little higher than the limit of attenuation. For light colored beers this attenuation is about 2-4% and for dark beers as much as 6% above the limit of attenuation. Export style beers can have an attenuation as close as 0.5% below the limit of attenuation. A difference between actual and limit of attenuation means that there are fermentable sugars left in the beer which are a vital part of the flavor profile, but larger percentages of these sugars result in in a less shelf stable beer.
 

Wolfy

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contrary to all the advice above, you can in fact start dropping the temperature prior to completion of fermentation

quote from braukaiser.com
True, but that is a very specific process that was developed for a very specific situation, and is it something you'd do yourself or recommend to another home-brewer?
 

felten

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IIRC in that braukaiser lager article he goes on to give a few more homebrewer friendly fermentation schedules.
 

kario

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contrary to all the advice above, you can in fact start dropping the temperature prior to completion of fermentation

quote from braukaiser.com
During the secondary fermentation (a.k.a lagering) the tanks are closed and the pressure build-up is controlled by a pressure sensitive bleeder valve. This system, called Spundungsapparat, ensures the proper carbonation of the beer during lagering. The German Purity Law prohibits the use of non-fermentation CO2 for beer carbonization. It is also more economical for a brewery to use the CO2 produced during fermentation.
This is an interesting fact....it begs the question from my simple brain: So how do they get fully carbonated beer into bottles? :blink:
 

warra48

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This is an interesting fact....it begs the question from my simple brain: So how do they get fully carbonated beer into bottles? :blink:
By kraeusening the beer at bottling. They add a small amount of unfermented or partially fermented wort, and it ferments and carbonates in the bottle.
 

kario

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By kraeusening the beer at bottling. They add a small amount of unfermented or partially fermented wort, and it ferments and carbonates in the bottle.
really? So this prevents the fully carbonated beer from foaming up etc when transferring from the vat to the bottle?

....and wouldn't that result in sediment in the bottle? Or do they filter it again? filter fully carbonated beer?.....sounds messy
 

donburke

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True, but that is a very specific process that was developed for a very specific situation, and is it something you'd do yourself or recommend to another home-brewer?

absolutely, we as homebrewers are afforded the luxury to try anything we can without the fear of it being a catastrophic business decision if it were implemented without success in a commercial environment

just as some say raise the temp, others say leave it constant, if you are patient enough, why not try dropping it ?
 

manticle

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Main reason is the re-absorption of byproducts. The above document offers a range of lagering time from 4 weeks to 6 months and if you're prepared to lager that long at 5 deg C then you're probably covered.

Also done under pressure so the beer carbonates itself. Difficult to replicate at home (for most of us anyway)
 

donburke

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Main reason is the re-absorption of byproducts. The above document offers a range of lagering time from 4 weeks to 6 months and if you're prepared to lager that long at 5 deg C then you're probably covered.

Also done under pressure so the beer carbonates itself. Difficult to replicate at home (for most of us anyway)
had this happen to me by accident, looks like my lager hadnt quite finished, kegged and stored in a fridge with no gas on it, come and tap the keg a month later and its carbed up, perhaps a little too carbed

could use of these to do it properly

http://www.craftbrewer.com.au/shop/details.asp?PID=1069
 

Oatlands Brewer

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Auto carbonation of beer...sounds brilliant but deadly :lol:
 

Wolfy

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absolutely, we as homebrewers are afforded the luxury to try anything we can without the fear of it being a catastrophic business decision if it were implemented without success in a commercial environment

just as some say raise the temp, others say leave it constant, if you are patient enough, why not try dropping it ?
As indicated in the quote you provided, they deliberately drop the temperature to stall the fermentation before it's complete (and they do that with years of experience and scientific knowledge and measurement). Hence, it's not catastrophic business decisions I'm worried about but catastrophic bottle bombs or similar injury-threatening consequences that potentially inexperienced home-brewers who do not have those years of experience, cannot measure or control their processes like a commercial brewery can, might face if they bottle deliberately stalled beer or add too much fresh wort when bottling.

As the quote indicates, the main reason the technique was originally developed was due to the German Purity laws not allowing the addition of CO2 for force carbonation. So while I have no objection to trying the process, I think it's risky suggesting it as a general-concept for home brewers who are not constrained by those limitations. If a home brewer had the experience with their processes, knowledge and equipment (eg kegging setup) and was trying to emulate a specific beer (eg Pilsner Urquell) then it would likely be a good experiment, but it could be risky for a newer brewer who uses bottles and does not have the experience and knowledge to safely apply the process.
 

donburke

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As indicated in the quote you provided, they deliberately drop the temperature to stall the fermentation before it's complete (and they do that with years of experience and scientific knowledge and measurement). Hence, it's not catastrophic business decisions I'm worried about but catastrophic bottle bombs or similar injury-threatening consequences that potentially inexperienced home-brewers who do not have those years of experience, cannot measure or control their processes like a commercial brewery can, might face if they bottle deliberately stalled beer or add too much fresh wort when bottling.

As the quote indicates, the main reason the technique was originally developed was due to the German Purity laws not allowing the addition of CO2 for force carbonation. So while I have no objection to trying the process, I think it's risky suggesting it as a general-concept for home brewers who are not constrained by those limitations. If a home brewer had the experience with their processes, knowledge and equipment (eg kegging setup) and was trying to emulate a specific beer (eg Pilsner Urquell) then it would likely be a good experiment, but it could be risky for a newer brewer who uses bottles and does not have the experience and knowledge to safely apply the process.
fair call wolfy, this method now carries the following warning


DONT TRY THIS IF BOTTLING
 

stux

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Main reason is the re-absorption of byproducts. The above document offers a range of lagering time from 4 weeks to 6 months and if you're prepared to lager that long at 5 deg C then you're probably covered.

Also done under pressure so the beer carbonates itself. Difficult to replicate at home (for most of us anyway)
This guy on another forum has been doing it with corny kegs...

http://www.biabrewer.info/viewtopic.php?f=...g+in+keg#p13233

quite an interesting process :)
 
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