Cold Crashing

[Yob]

~4-7 days.. Ive crashed at 0 for 2 days when I was in a hurry once, but if you have the time, 4 days

 

[ash2]

I have one that's been sitting since 2/12/13 Yob I just havn't had time to bottle it yet tastes & smells ok

 

[mrsupraboy]

Can someone correct me if I'm wrong bit when u say cold crash Ur meaning chill to 2'c or colder before putting the yeast in for a day or 2 then Ur warming it up to 12 - 18'c and putting the yeast in to forment.

Is that correct. Sorry I'm new to all of this.

And when Ur saying crash cold before bottling are you meaning once fermentation is done turn down the temps again before bottling.

Is that correct and if so does it apply to kegging

Also what styles of beer would and wouldn't you do this to.

 

[davedoran]

Hey Supraboy,

No the idea is to ferment as you would normally (18deg for an ale 12deg for lager etc) with your wort and yeast in the fermentor.
After this has finished fermenting it is chilled down to 2 deg.
With referral to largering it is done to give lager style beers that crisp taste and clarity which is not always found with ales.
If you are kegging you would still do this process.

Subject to correction here but the ones I wouldn't crash chill would be stouts, dark beers, cloudy beers, wheat beers.

Hope it helps somewhat.

 

[mrsupraboy]

Would chilling it straight down in a keg be the same as crash chilling or not really

 

[DJ_L3ThAL]

Not really, because crash chilling in your fermenter is to leave the dropped out yeast behind when you transfer to the keg. Sure in the keg you will get it to drop out, but to the bottm of the keg where the beer poured out comes from at first so you'd end up wasting beer on a few cloudy couple of pints or more.

 

[BeerNess]

Would chilling it straight down in a keg be the same as crash chilling or not really

not really, The idea of crashing is to drop as much shit as possible out of your beer before it is kegged or bottled, to avoid those muddy pours.
Edit DJ got in first lol...im a damn slow typer

 

[zappa]

And if you can get your head around using plastic in your beer, adding some polyclar and cold crashing for around 4 days will really clear your beer up, with less tendency for off flavours to develop in your beer after kegging/bottling. Have only used it a few times myself, but have been extremely happy with the results.

 

[mrsupraboy]

ok thanks peeps

 

[Jason_brews_beer]

Should i crash chill a Mangrove Jack Pale Ale K&K??? After reading this post I think its a good idea but not sure i can chill to 2 deg... Don't have a ferment fridge yet...

 

[New_guy]

Great Topic

As I aint that sharp, in summary the cold crashing process is (with fridge):

1. Ferment as per normal routine
2. Ensure fermentation complete - FG steady for 3 days
3. Chill FV to 2 deg C (in fridge)
4. Leave FV in fridge for further 4 - 7 days
5. rack to secondary if preferred
6. Bottle as per normal routine

 

[Stimsoni]

If you cold crash in secondary is it ok to bring back up to ambient temp after bottling or kegging.

 

[Yob]

If bottling, the beer will warm up anyway, if kegging, it's better to be cold when you force carb it.

 

[philmud]

Should i crash chill a Mangrove Jack Pale Ale K&K??? After reading this post I think its a good idea but not sure i can chill to 2 deg... Don't have a ferment fridge yet...

The beer you mention would benefit from cold crashing, but without a brew fridge you won't be able to. If you want clearer beer you've still got a couple of options. First, let your beer sit in the fermenter for a couple of weeks. This will allow more yeast to drop out. Second, add finings a couple of days before you bottle/keg.

 

[joshF]

On the whole CC topic, there's a bit of a grey area about 'when' to crash chill. Of course you need to wait until fermentation has finished but there is very little mention of how long after fermentation is finished.

Say I leave all my beers for 10 days before even doing a hydro sample, if say i used an irish ale yeast or a wheat yeast, these are typically finished after 4 or 5 days.

So if the purpose of cold crashing is to drop everything out of suspension and clear the beer up, could this not be done immediately after fermentation is finished at say day 4 or 5? If the theory of the yeast cleaning up fermentation biproducts at fermentation temperatures has the same impact as cold crashing, then why do we wait that extra few days or few weeks before cold crashing? Or why not chill for 24 hours and then filter?

Just interesting in everyonese opinions or if there is some science behind it

 

[big78sam]

[SIZE=10pt]I’ve had occasional instances in the past where immediately after fermentation has finished I have off flavours. Rather than ditching I was advised to let the yeast “clean up” after itself and by leaving a few days this has happened. I usually wait 3 or 4 days after fermentation is complete (and do a diacetyl rest if needed during this time) before crash chilling. Is this required or “best practice”? I don’t know. I just do it as part of my fermentation regime as anecdotal evidence has shown it can be beneficial at times.[/SIZE]

[SIZE=10pt]On another related issue, I understand the two main factors for getting yeast and other stuff to drop out is both time and temperature. I have traditional done a crash chill at 1 or 2 degrees for a few days and got OK clarity. Doing a run of lagers for the first time recently I crashed down to -1 and left for a couple of weeks. The beer was crystal clear into the keg. So for me I will now crash chill at -1 and leave for at least a week (i.e. lower temperature and more time).[/SIZE]

 

[stm]

So if the purpose of cold crashing is to drop everything out of suspension and clear the beer up, could this not be done immediately after fermentation is finished at say day 4 or 5? If the theory of the yeast cleaning up fermentation biproducts at fermentation temperatures has the same impact as cold crashing, then why do we wait that extra few days or few weeks before cold crashing? Or why not chill for 24 hours and then filter?

I think the "yeast cleaning up after itself" and "cold conditioning" are different things. You allow the first to happen and then you do the second. The yeast won't be able to actively "clean up after itself" if you put it to sleep at 2 degrees.

 

[joshF]

Agreed they are different things but the whole 'cleaning up after itself' is an extremely grey area. What exactly are the yeast doing? They've eaten sugar, shit out alcohol and burped out co2.

It sounds very much like the additional week after fermentation has finished is simply a matter of gravity doing its thing by dropping yeast, trub, hop particles etc etc to the bottom of the fermenter. Sure this extra week or so makes the chilling phase alot faster and probably yields greater results in terms of clarity, but chilling immediately after fermentation for 2 weeks vs 1 week would seem to yield the same results.

As we know, dropping the temperature dramatically increases the speed of this 'dropping / clearing' effect and clears the beer up significantly faster. So what exactly are we waiting the extra week for after fermentation before chilling it?

Has anyone done a comparison of this? I've got AndrewQld's coopers recipe at the moment with s04 which hit 1.006 thismorning and am tempted to transfer half into a secondary, chill that for 24 hours then filter it at 0.35 into a keg, then leave the other 12 or so litres in the primary fermenter and chill it for a week or so, keg and then compare the results.

Surely there's a scientific explanation for it?

 

[big78sam]

Agreed they are different things but the whole 'cleaning up after itself' is an extremely grey area. What exactly are the yeast doing? They've eaten sugar, shit out alcohol and burped out co2.

It sounds very much like the additional week after fermentation has finished is simply a matter of gravity doing its thing by dropping yeast, trub, hop particles etc etc to the bottom of the fermenter. Sure this extra week or so makes the chilling phase alot faster and probably yields greater results in terms of clarity, but chilling immediately after fermentation for 2 weeks vs 1 week would seem to yield the same results.

As we know, dropping the temperature dramatically increases the speed of this 'dropping / clearing' effect and clears the beer up significantly faster. So what exactly are we waiting the extra week for after fermentation before chilling it?

Has anyone done a comparison of this? I've got AndrewQld's coopers recipe at the moment with s04 which hit 1.006 thismorning and am tempted to transfer half into a secondary, chill that for 24 hours then filter it at 0.35 into a keg, then leave the other 12 or so litres in the primary fermenter and chill it for a week or so, keg and then compare the results.

Surely there's a scientific explanation for it?

I have read about yeast geting rid of, or reducing, diacetyl and acetaldehyde after fermentation has complete and that dropping the temperature stops or severly slows this "clean up". I agree it's a bit of a grey area to me. Maybe an "expert" like Thirsty Boy could comment here (is he still around?). My practie is leave at or slightly above fermentation temps for a couple of days, then crash chill. That way I've got both bases covered.

This reminds me, I should go back and revisit the yeast book.

 

[stm]

John Palmer can overstate some issues at the homebrew scale and be a bit dogmatic (eg, splashing hot wort and slow-chilling), but this is what he says in How To Brew on topic:

The conditioning process is a function of the yeast. The vigorous, primary stage is over, the majority of the wort sugars have been converted to alcohol, and a lot of the yeast are going dormant; but there is still yeast activity. During the earlier phases, many different compounds were produced by the yeast in addition to ethanol and CO2, e.g., acetaldehyde, esters, amino acids, ketones- diacetyl, pentanedione, dimethyl sulfide, etc. Once the easy food is gone, the yeast start re-processing these by-products. Diacetyl and pentanedione are two ketones that have buttery and honey-like flavors. These compounds are considered flaws when present in large amounts and can cause flavor stability problems during storage. Acetaldehyde is an aldehyde that has a pronounced green apple smell and taste. It is an intermediate compound in the production of ethanol. The yeast reduce these compounds during the later stages of fermentation.

The yeast also produce an array of fusel alcohols during primary fermentation in addition to ethanol. Fusels are higher molecular weight alcohols that often give harsh solvent-like tastes to beer. During secondary fermentation, the yeast convert these alcohols to more pleasant tasting fruity esters. Warmer temperatures encourage ester production.

Towards the end of secondary fermentation, the suspended yeast flocculates (settles out) and the beer clears. High molecular weight proteins also settle out during this stage. Tannin/phenol compounds will bind with the proteins and also settle out, greatly smoothing the taste of the beer. This process can be helped by chilling the beer, very similar to the lagering process. In the case of ales, this process is referred to as Cold Conditioning, and is a popular practice at most brewpubs and microbreweries. Cold conditioning for a week clears the beer with or without the use of finings. Fining agents, such as isinglass (fish bladders), Polyclar (plastic dust), and gelatin, are added to the fermentor to help speed the flocculation process and promote the settling of haze forming proteins and tannins. While much of the emphasis on using finings is to combat aesthetic chill haze, the real benefit of dropping those compounds is to improve the taste and stability of the beer.