Cold crash

[jam]

What is cold crash and how long should you leave it for ?

 

[Fil]

Primarily used with beers its simply at the end of primary fermentation, chilling a brew down to ice cold temps will promote more clarity as the cold helps suspended solids drop out of suspension quicker than when warm

Also when kegging the reduction in beer temp aids the conditioning by excess pressure as the cold beer is more accepting to dissolved co2. And if chilled down sufficiently and its fairly humid, the condensation on the keg exterior is a pretty good fill level indicator too.

 

[Bigcol49]

Hi!
@Fil said it all :thumb1:

 

[svenito]

Wait, how long for? Well, some people are happy with 2-4 days, others a week, others just a bit more again. I tend to do a few days to a week. I dropped the temp on my current one last night and I plan to bottle next Wednesday. That's because that's how my schedule fits. I've cold conditioned for 3 days with good results too.

 

[-Bezza-]

Being limited to weekends only, I cold crash for a week at fridge temperatures. When it come to bottling, I have a semi-clear beer with all the gunk nicely compacted at the bottom of the FV. It's a massive improvement from bottling from warm.

I understand you don't want to hold in cold crash for too long as a) you'll take nearly all the yeast out of suspension which can mean there's nothing left to carb with and b) you don't want a beer sat on dead yeast. But too long is several weeks, perhaps 5+, rather that one or two.

 

[svenito]

I understand you don't want to hold in cold crash for too long as a) you'll take nearly all the yeast out of suspension which can mean there's nothing left to carb with and b) you don't want a beer sat on dead yeast. But too long is several weeks, perhaps 5+, rather that one or two.

Conversely I've also read that people cold condition for months without any issues. They don't specify if this is on the yeast or not, but I doubt that all the yeast would ever drop out, but I haven't tried this myself. As to the dead yeast affecting flavour, I've heard from people that there was no off flavours having left the beer on the cake for two months. As per usual with homebrewing, there's a lot of contractictory information, but I would agree with @-Bezza- that anything up to one month should definitely be fine.

 

[Cwrw666]

Consider that when beer is bottled and primed - it will then be sat on a cake of yeast much of which will be dead. And bottled beer will keep for a year. So cold crashing for a few weeks will not be a problem taste-wise. But it will take longer to carb up.

 

[Bigcol49]

Hi!
"Cold crash" is a term originating in the USA. It can mean anything from a rapid cooling for a couple of days to a longer period of cold conditioning, either on or off the trub.

 

[Drunkula]

I've heard from people that there was no off flavours having left the beer on the cake for two months

John Palmer says with homebrewing vessels it's just not a problem as they've got wide bottoms and the pressure on the yeast is nothing. I huge commercial brewing containers with conical bottoms the pressure on the yeast can get really high and that's what causes the breakdown.

 

[svenito]

John Palmer says with homebrewing vessels it's just not a problem as they've got wide bottoms and the pressure on the yeast is nothing. I huge commercial brewing containers with conical bottoms the pressure on the yeast can get really high and that's what causes the breakdown.

Now that you mention it, I've heard that distinction too.

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[terrym]

If you are only doing kits or extract beers, even with a small minimash or a grain steep, there is no real need in my experience to crash cool for longer than two days to finish dropping the yeast. And other than in the summer months when I do use a fridge, normally it just goes into the coldest place I have. And the beer will be clear or nearly clear provided its had long enough in the FV to ferment and finish off. Given time, patience and gravity the finished beers will be clear and with only a tiny layer of yeast on the bottom of the bottles.
However there's a lot more going on in AG beers, including suspended proteins, and that may well be the reason why crash cooling is much more important to the AG brewer.