Cold Crashing

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smccarter

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Just a quick technique question before I cold crash 2 beers... I've never done this before, and want to be successful on my first attempt.

I've read a few posts on the subject and just want to validate the technique I'm going to use.

I'll remove the airlocks and replace with aluminum foil secured with rubber bands. I'll place the carboys in the freezer and set the temp controller to 40 degrees. I'll leave at that temperature for 18-24 hours.

Does that sound about right?
 
Opinions vary, but I would leave it for 1-3 (or more) days. There's a lot of thermal mass. It'll take a while just to get the temperature down. For me, 40 is a little high. I go as close to freezing (without freezing) as I can get.

edit: Are you crashing a primary or secondary vessel?

I use to leave an S type airlock on during cold crashing, but now prefer minimizing the chance of exchange of ambient air by using foil and a rubber band.



Secondary Cold Crash . . .

ColdCrash2.jpg
 
I use S airlocks with StarSan inside, so I just leave them be. Never had a problem.
 
I have had success with cold crashing for only about 24 hours.

Curious, why remove the airlock? I have never done that.
 
I have had success with cold crashing for only about 24 hours.

Curious, why remove the airlock? I have never done that.

From what I've read, cold crashing creates a vacuum in the carboy. People have stated in some of the threads on HBT, and on other boards, that they've experienced "suck back"... meaning that the liquid in the airlock is being sucked into the carboy as a result of the vacuum. One suggestion was to remove the airlock and replace it with a piece of sanitized aluminum foil. Sounded reasonable to me.
 
From what I've read, cold crashing creates a vacuum in the carboy. People have stated in some of the threads on HBT, and on other boards, that they've experienced "suck back"... meaning that the liquid in the airlock is being sucked into the carboy as a result of the vacuum. One suggestion was to remove the airlock and replace it with a piece of sanitized aluminum foil. Sounded reasonable to me.

The possibility of suck-back is why you put StarSan in the airlock. If it gets in the beer, no biggie. Also, the S airlocks, unless overfilled with liquid, aren't prone to that problem.
 
Agreed...i leave my S type airlock on. I am also a big fan of buckets so it would be hard to remove the airlock and then have to cover the hole...
I also cold crash for a minimum of 2 days...sometimes longer. it wont hurt anything to let it sit...but i alwasy leave it for 2 days since it takes a while to get down in temp. then you want to give it time once it is at temp to drop everything.
 
The "vacuum" comes from the fact that, as the beer is cooled, the gas in the headspace above the beer "compacts" and more dense. This effect pulls air in from the outside through the airlock.

If the headspace is relatively small, the resulting draw in will also be small. If the airlock is properly filled, chance of getting any of the airlock liquid pulled into the fermenter should be minimal.

On the other hand, if the size fermenting vessel has not been chosen properly and there is a large head space and the airlock is overfilled with liquid, the chances of draw back are greatly increased.

I don't ever remember having liquid sucked into any of my fermenters in nearly 20 years of brewing.
 
From what I've read, cold crashing creates a vacuum in the carboy. People have stated in some of the threads on HBT, and on other boards, that they've experienced "suck back"... meaning that the liquid in the airlock is being sucked into the carboy as a result of the vacuum. One suggestion was to remove the airlock and replace it with a piece of sanitized aluminum foil. Sounded reasonable to me.

yup it will do that. you can use foil or just let what ever you are using in your airlock. (vodka star san) get sucked in a bit. No big deal there. The problem is when you still have a blow off tube attached you run a risk of sucking in alot of fluid.

on the cold crash its better if you drop your temps slower to keep your yeast from puking up any off flavors. I like to do it over the course of a day and leave it at temp for 24 hrs.
 
on the cold crash its better if you drop your temps slower to keep your yeast from puking up any off flavors. I like to do it over the course of a day and leave it at temp for 24 hrs.

This sort of slow downward temp adjustment really isn't necessary.

If you put 5 gallons of 68*F beer into a fridge that's set at 35*F, it's going to take some hours for the liquid to cool to 35*F.

Also, the idea that "quickly" dropping the temp of a completed batch (after the yeast have already finished fermenting, have dropped out and gone nighty-night) is, IMO, a brewing myth. That sort of comment gets posted every so often, but I've yet to see anything to back it up. It's likely a conclusion that someone once leaped to based on the known risk of off-flavors being produced when an active fermentation is exposed to sudden, significant fluctuations in temperature.
 
My problem with cold crashing is that the point is too settle the yeast in a low temp which I get but for me, and I assume much others, I have to move the carboy out of the fridge to keg so I feel as if I'm shaking the yeast up again in to the beer. Any suggestions?
 
If you leave it in the fridge for at least 2-3 days, the yeast cake will compact pretty tightly in my experience. If you are fairly gentle with moving the carbon out and getting it set for racking, you shouldn't stir up too much of the cake, if any. The longer you can cold crash, the tighter the cake.
 
I cold crash for a couple days, then when i do move it out of the keezer i put it on counter and let it settle while i sanatize my keg and equipment. since it is still cold it will settle back down fairly quick. never have issues and my beers come out clearer than ones i have had where people use gelitin or irish moss. since i started cold crashing all my beers i dont use either of those and my beers come out crystal clear...:D
 
Does cold crashing negatively effect bottling/carbing up? Is there anything I need to account for? I bottle with table sugar. I have a cream ale in a new temp controlled fridge and I was thinking of cold crashing for the first time.
 
I dont think it has any effect on bottling or carbing...of course it wont start to carb until the beer warms up enough for the yeast to wake up and eat the priming sugar. Make sure you give it the full 2 weeks min though since there will probably be less yeast left in beer to carb. i have also found that you will have less gunk on bottom of bottle when you cold crash first too since all the other crap in your beer will settle out and what is left is very fine yeast. I think cold crashing is a very simple and easy technique to clear your beers with little to no effort. i am a fan of it!
 
seckert said:
I dont think it has any effect on bottling or carbing...of course it wont start to carb until the beer warms up enough for the yeast to wake up and eat the priming sugar. Make sure you give it the full 2 weeks min though since there will probably be less yeast left in beer to carb. i have also found that you will have less gunk on bottom of bottle when you cold crash first too since all the other crap in your beer will settle out and what is left is very fine yeast. I think cold crashing is a very simple and easy technique to clear your beers with little to no effort. i am a fan of it!

ok thanks for the response.
 
Does cold crashing negatively effect bottling/carbing up? Is there anything I need to account for? I bottle with table sugar. I have a cream ale in a new temp controlled fridge and I was thinking of cold crashing for the first time.

I've observed no negative effect at all on bottle carbing. I cold crash mine for 5-7 days at 35-36*F and prime/bottle it cold. When I move the bucket out of cold crash, I do so carefully and carry out the transfer to the bottling bucket within a few feet of the lager/crash chamber.

Another useful benefit of cold crashing is that there will be less yeast trub in the bottom of each bottle when it comes time to pour.
 
I'm absolutely amazed with the difference. I cold crashed 2 beers recently.... the first time I've done this. I also added geletin to the kegs - again... first time. The beer is crystal clear... and I mean CRYSTAL clear. I've never had a truely clear beer before these 2. This is a process added from this point forward. I think I'll rack to secondary, add geletin, and cold crash in a carboy though to shorten the process. Once clear, I'll bottle for friends and keg the rest.
 
I have had success with cold crashing for only about 24 hours.

Curious, why remove the airlock? I have never done that.

I left the airlock on and didn't have any problems. No suck-back at all. That's a problem with reading too many posts on HBT. We read and begin to over think things I suppose. Good advice, but maybe too much of it sometimes.
 
I left the airlock on and didn't have any problems. No suck-back at all. That's a problem with reading too many posts on HBT. We read and begin to over think things I suppose. Good advice, but maybe too much of it sometimes.

It's not an issue if you use an S airlock (aka, "double bubble") and put Star San in it.
 
I'm absolutely amazed with the difference. I cold crashed 2 beers recently.... the first time I've done this. I also added geletin to the kegs - again... first time. The beer is crystal clear... and I mean CRYSTAL clear. I've never had a truely clear beer before these 2. This is a process added from this point forward. I think I'll rack to secondary, add geletin, and cold crash in a carboy though to shorten the process. Once clear, I'll bottle for friends and keg the rest.

Try cold crashing without using the gelatin and I bet you will be just as happy with the results. I have stopped adding irish moss and using gelatin and I have not noticed any difference. I don't do a secondary either unless I am racking on top of something. Still comes out crystal clear. Just a thought since you can save some $ and time if you eliminate some of that stuff. :mug:
 
So much advice. So many different "experts" giving advice. It makes your head spin sometimes. Folks even argue their point.... Angrily at times.

Thanks for the info though. I will say that using whirlfloc during the boil, cold crashing with geletin for 48+ hours, produces very... VERY clear beer. Could be that your process works very well, but this one I've seen work with extremely clear beer. I'll probably stick with this one for the time being. Not to say that I won't try your method later.
 
So much advice. So many different "experts" giving advice. It makes your head spin sometimes. Folks even argue their point.... Angrily at times.

Thanks for the info though. I will say that using whirlfloc during the boil, cold crashing with geletin for 48+ hours, produces very... VERY clear beer. Could be that your process works very well, but this one I've seen work with extremely clear beer. I'll probably stick with this one for the time being. Not to say that I won't try your method later.

hey...best way to do it is the way you like to do it. sometimes i have tried something someone suggested and afterwards decided never again will i do it that way. Or on the flip side sometimes i have tried something and been really impressed. As long as you are having fun homebrewing and enjoy your beer thats all that matters! :mug:
 
Has anyone experienced any negatives from cold crashing? I'm very green in this hobby (lifestyle a better term?) and I enjoy all the insight this community provides!
 
Has anyone experienced any negatives from cold crashing? I'm very green in this hobby (lifestyle a better term?) and I enjoy all the insight this community provides!

sometimes I forget to cold crash it on time and when I do realize it, I have to wait the 2-3 days until I can keg it. That's the only one I can think of...:mug:
 
Has anyone experienced any negatives from cold crashing? I'm very green in this hobby (lifestyle a better term?) and I enjoy all the insight this community provides!

Oxidation is a problem that can happen. The cold beer and air take up less space in the carboy and there is a significant amount of air pulled into the fermentor.
 
Oxidation is a problem that can happen. The cold beer and air take up less space in the carboy and there is a significant amount of air pulled into the fermentor.

The CO2 that was in the fermentor before this should protect the beer from this as CO2 is heavier than air. so even if the air is sucked in there will be a barrier of CO2...unless I am missing something it should work like that anyway...
 
seckert said:
The CO2 that was in the fermentor before this should protect the beer from this as CO2 is heavier than air. so even if the air is sucked in there will be a barrier of CO2...unless I am missing something it should work like that anyway...

I could see this as an issue in my particular circumstance. I currently brew 2.5 gallon batches in a 5 gallon setup. Perhaps the extra head space could allow oxidation or at the very least be more apt to in this instance?
 
Ok what is the point of cold crashing I'm new to brewing so trying to learn is this done when bout ready to keg.
 
I only use the foil because I got suck back on two straight beers. One when lagering and one with just a cold crash. And while star san in beer is no biggie...I'll pass. I do smaller batches so I have less thermal mass and probably drop the temp quicker than 5 gallons or bigger. I bet the larger the batch size the less likely it is for suck back.
 
I'd try looking under the cushion of the couch. You're definitely missing something. :drunk:

I looked under the couch but didnt find anything there! So please enlighten me as to what i am looking for as it will aid me in the search! :pipe:
 
Ok what is the point of cold crashing I'm new to brewing so trying to learn is this done when bout ready to keg.

Crashing helps to clear the beer of "some" of the yeast and other bi-products still in suspension. Drops the heavier particulates to the bottom. It also compacts the yeast cake and makes it a little easier to rack off.

I find that I get considerably less sediment in my bottles than those beers that I don't crash.

I just crashed my most recent two batches outside. Our recent cold spell had us at about 32 overnight and 50 during the day. I bottled them yesterday after sitting on my patio for 3-4 days.
 
Thanks for the info.... lucky you we have been in the negatives here recently and highs in the teens
 
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