# Cold crashing rate



## josho_28 (29/6/18)

Is there a max rate of cooling cold crashing should be done at? 

In ‘How to Brew’ Palmer says to reduce the temp at max 1 deg C per day in one part and 6 per day in another but regularly hear of people ‘crashing’ as fast as possible in 1-2 days so I’m confused..? 

From the book: “The point of slow cooling is to prevent thermal shock of the yeast cells and subsequent excretion of fatty acids and other lipids. These lipids can interfere with head retention and will readily oxidize, creating stale flavors.” ‍


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## Ben Davies (29/6/18)

I cold crash rapidly as in just set stc to 0 and let her go. Or in summer will do it in two steps 10 then 0 or -1.

Lager yeast can continue operating cool but i doubt at -1 so it makes sence to lower them slowly. I have done this but lately ive been opting for more shody practices so takr my advice with a grain of barley.

Recent hoppy lager was fermented 18c ramped 21c then crashed and carbed and in the glass less than two weeks! Yep it dont taste as clean as a lager but its good will do with spme conditioning though...


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## Thomas Wood (29/6/18)

I currently have a Pacific Ale fermenting at 20*C as we speak. I plan on Cold Crashing hopefully on Monday if the FG is low enough.
I will probably go down to 14*C, then 8*C the next day, then leave it on 2*C for a few days after that. I'll add finings when I start the cold crash too.
Should be noted that this is only my 3rd brew, so I in no way know what I am talking about haha


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## wide eyed and legless (29/6/18)

josho_28 said:


> Is there a max rate of cooling cold crashing should be done at?
> 
> In ‘How to Brew’ Palmer says to reduce the temp at max 1 deg C per day in one part and 6 per day in another but regularly hear of people ‘crashing’ as fast as possible in 1-2 days so I’m confused..?
> 
> From the book: “The point of slow cooling is to prevent thermal shock of the yeast cells and subsequent excretion of fatty acids and other lipids. These lipids can interfere with head retention and will readily oxidize, creating stale flavors.” ‍


Depends on the ABV but -1C to - 2 C for a couple of days should get everything settled out.


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## Kev R (29/6/18)

Don't know about freezers, but a fridge and the large mass of 20+ liters of brew takes a few days to get down to 1or 2 deg. mine does anway


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## Ben Davies (29/6/18)

Get a freezer . But it does strain your back lifting in and out.


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## RobinW (29/6/18)

Kev R said:


> Don't know about freezers, but a fridge and the large mass of 20+ liters of brew takes a few days to get down to 1or 2 deg. mine does anway


I have an upright freezer that fits 2 x 30L fermenters. It drops both fermentors to 1C in about 6 hours.
I normally give it a day to crash then 2 days @ 1C then filter into a keg.
I also add gelatin to the keg. Works for me.


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## Quokka42 (30/6/18)

Combining the scientific studies with the physics of a small deep freeze and 21l of wort if you set your controller for 0-2C and let the sensor dangle in the middle or loosely tape to FV it will settle with no problems in 24h. Sometimes your mash doesn't go quite right, and you should leave it 48h or until it appears to be clearing.


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## Dr_Rocks (30/6/18)

Quokka42 said:


> Combining the scientific studies with the physics of a small deep freeze and 21l of wort if you set your controller for 0-2C and let the sensor dangle in the middle or loosely tape to FV it will settle with no problems in 24h. Sometimes your mash doesn't go quite right, and you should leave it 48h or until it appears to be clearing.


I agree with Quokka, I've only ever cold crashed by immediately switching the fermentation fridge on, so that it reaches 0 - 1 degrees as quickly as possible. Generally I leave it at 1 degree for a whole day, then gelatine for another day and it's as clear as any commercial beer i've ever seen.


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## rossbaker (30/6/18)

I've also only ever rapidly cold crashed, but have also recently come across Palmer's advice and have been wondering if it is better practice. I've also started to suspect that, despite every effort to stop it, cold crashing in a standard fermenter does introduce o2. I've recently obtained a kegmenter so at least now I will be able to pressurise and seal it fully before dropping the temp. Really not sure how to achieve this in a standard plastic fermenter.


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## Wobbly74 (30/6/18)

I have a 28L stainless kegmenter and do likewise, but I've also been fermenting in cubes as well. With these I've fitted a gas post in the lid and disconnect the blow off tube when I cold crash, then lightly pressurise before packaging. Stops any ingress of o2. Not sure if you could do the same in a bucket.


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## shmang (30/6/18)

For ales I generally do it in two steps.
Drop to 11-12°C in the first step, then down to 0-1°C. It takes about 12 hours to get down to temp, each step ends up being about 24 hours by the time it gets down to temp then get home from work/remember to start the next step. Couple of days to a week at 0°C then it's into a keg.

Lager's do it in one step, I leave it 0°C for a week or two then into the keg.


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## Outback (30/6/18)

Doesn't the name cold "crashing" infer getting to cold as quick as possible? 
Palmerr's method infers child ramping to me, and down a gentle ramp at that! 
I'm not saying he is wrong or there is a flaw in the methodology, just the nomenclature is ambiguous.


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## wide eyed and legless (1/7/18)

No real need to use any clearing agent when cold crashing, any undesirables will drop out at the cold temperature. I haven't a clue why its called cold crashing or if it makes any difference how quick the temperature drops. Charlie Bamforth discusses it in this podcast at around the 41 minute mark.


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## Black Devil Dog (1/7/18)

If you want to re-use your yeast, or you want to lager your beer, it's advisable to lower the temperature slowly so as not to stress the yeast.

As for preventing o2 getting in, there was a bit of discussion about it some time ago and several ideas were tossed around.

The photo below is what I've settled on.

Once the fermentation is pretty much done, I remove the blow off tube and attach these camelbacks.
The idea is that they'll capture co2 that's still escaping and store it until I want to drop the temp. Then the co2 is drawn back into the fermenter, preventing oxygen getting in.

It should work with any fermenter with a lid.


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