What is this "crash cooling" some of you speak of???

[Beernewb]

I am 7 days into my cream stout, its resting quietly at 67 degrees, no visible signs or sounds coming from the airlock and the beer has retreated to resemble a smooth lake with a few white lilies on top. i am going to give it another week before taking a hydrometer reading and potentially transferring to my bottling bucket....oh, my question? what s this crash cooling people talk about? do i need to do this before bottling? i have the ability through my temperature controlled freezer, but what are the advantages/disadvantages?
tia

 

[WortMonger]

I would crash it down to 33*F for a couple of days before you want to take gravity and transfer. It will really cause a lot more yeast to drop and compact on the bottom of your fermenter and then allow for a cleaner transfered beer into your secondary or bottling bucket in your case. This is the Crash Cooling you hear about. It is simply taking your beer down to almost freezing to allow yeast to stop and drop. Lagers you will want to drop a few degrees a day, but ales can pretty much be dropped immediately after primary fermentation is completed.

 

[Cpt_Kirks]

If you leave it in the primary longer, say three weeks or so, does crash cooling really do much?

 

[eddie]

It can. Mostly it helps to settle out excess yeast and proteins dissolved in the beer which results in a clearer finished product and reduces chill haze.

 

[adamd]

If you plan on filtering through a holding keg and into a serving keg, would it make crash cooling obsolete?

 

[ajf]

The purpose of crash cooling is to remove chill haze which some people find objectionable in clear beers. It does nothing for flavor. If you can notice chill haze in a stout, then by all means crash cool. Otherwise, I'd leave that procedure for a lighter beer.

-a.

 

[eddie]

As far as the excess yeast goes, the answer is yes. Filtering can remove almost all of the yeast from the beer but it won't remove chill haze. Chill haze is produced by proteins dissolved in the beer and filtering won't remove them. The only things I know of that will reduce the effect are cold crashing, extended secondary aging, gelatin/isinglass fining or the use of polyclar.

I should add that chill haze is purely aesthetic and does not impact the taste or body of the brew.