Cold crash purpose

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UglySister

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Is the purpose of a cold crash to help with clarity? If so... How does it work. Cold crash in secondary for 24 hours then rack to keg and return to frig to carbonate? Is that right?
 
Is the purpose of a cold crash to help with clarity? If so... How does it work. Cold crash in secondary for 24 hours then rack to keg and return to frig to carbonate? Is that right?

Cold crashing allows any yeast and or hops in suspension to drop out, allowing you to siphon the clearer beer off the top. If you keg you will be cold crashing anyway but this keeps more undesirable matter from making it in the keg to start with.
 
no need to secondary. Bring your fermenter down to say 33* and let it sit a few days. This will cause "stuffs" to drop out and give you a clear beer.
 
Also for highly hopped beers oxidization is a common worry, a lot of us do complete enclosed transfers to avoid this, cold crashing can suck o2 back into the fermentor.

Just a heads up
 
If you use a one piece airlock or a blow-off tube, the air and liquid will not be pulled into the fermentator. I always cold crash.

-Joe
 
Use gelatin to get even better results. Cold crash your primary fermenter for 24-48 hours, then add 1/2 teaspoon of gelatin (knox or generic) that has been dissolved in about a cup of water at 150 degrees to pasteurize it. dump it in the keg with the beer when you rack it in. it really makes the proteins and yeast settle out. you'll get really clear beer.
 
If you use a one piece airlock or a blow-off tube, the air and liquid will not be pulled into the fermentator. I always cold crash.

-Joe

Using a blow off tube with cold crashing is the largest source of "one gallon of sanitizer sucked into my beer" posts.

A one piece "s style" airlock allows air to pass without sucking the sanitizer inside. A blow off tube will likely suck sanitizer in........ It can also start a reverse siphon and suck all the sanitizer out of your catch container.
 
Seems to me that either a 1-piece or a 3-piece airlock will allow air to come back in, just as easily as it lets air out. I don't understand what it is about either design that would make air travel one directional.

I cold crashed in my primary for years and just recently switched to cold crashing in my kegs as part of my current focus on reducing oxidation. I think most of my problem was that I wasn't adequately purging my kegs, but I also think cold crashing with an airlock isn't ideal for a couple reasons.

First, whenever I went to transfer my cold crashed beer from my primary to my keg, the liquid was still in my 3-piece airlock but there wasn't a vacuum inside my primary. The only explanation I could come up with is that air came in to fill up the space. Granted, I couldn't actually see that air was coming in, but I also couldn't see that the airlock was keeping air out. I'm just trying to reason this out.

Also, we know that oxygen dissolves more easily at colder temps than at warmer temps, which suggests any oxygen in the head space is more likely to be dissolved into the beer during the cold crash storage period and especially during transfer than with a beer that's at ferm temps.

I don't know if the amount of oxygen I was picking up during the cold crash and subsequent transfer is meaningful or not, but I do know that my oxydation problem is gone now (again, this probably has more to do with me being more fanatical about purging the keg). I also know that gelatin clears the beer just as effectively either way, so I'm not willing to take the added risk of crashing in the primary. Plus, cold crashing in my keg as opposed to my primary gets my beer on gas 24-48 hours sooner, which means it's in my glass 24-48 hours sooner! YMMV.
:mug:
 
Using a blow off tube with cold crashing is the largest source of "one gallon of sanitizer sucked into my beer" posts.

A one piece "s style" airlock allows air to pass without sucking the sanitizer inside. A blow off tube will likely suck sanitizer in........ It can also start a reverse siphon and suck all the sanitizer out of your catch container.

I have never experienced a blow off tube pulling fluid into the fermenter, but I have always done 5 gallon batches.
 
Having done both methods I prefer gelatin fining the beer is clear as hell when done properly. Even with the s airlock you can get suck back into the fermenter (ask me how I know this lol!!!!) I tried both 3 piece and s shape.

I primarily use brew buckets so the oxygen exposure is minimal when transferring from ferm to keg....yes I use a tube from the fermenter to the keg with a sanitized hop bag to catch any big particles and leave the lid on the top of the keg. After topping up the keg I hit with co2 and purge 10-12 times to clear any o2 out at 30 psi. I usually rock the keg after purging to help get a little co2 into solution. Then drop in the kegerator. I am sure I get a little o2 during transfer but not enough to make me lose sleep at night. My two cents
 
When I gave this a try I used a glycol as brewtech chiller to drop the fermenter down to 34 f it work but within about five minutes I could see fluid going up the blowoff tube from the catch bucket about halfway after only a minimal temp drop. Tried 3 piece same issue and with s shaped.
 
I cold crash everything now since I set a chest freezer with a InkBird controller. Just drop down to 33 and walk away for a few days or weeks. Clear clean flavored beer. Too easy not too.
 
I don't really care about "clear beer" but I don't want a pile a sediment in my bottles so I cold crash if I am bottling. My usual method is to put my fermentor in an ice chest, pull out the airlock and tape a cotton ball soaked in StarSan over the hole, fill the ice chest with ice, add a gallon of water, cover with a sleeping bag, and bottle the next day. This gives the trub layer a peanut butter consistency that I couldn't siphon if I wanted to, but still leaves plenty of yeast in suspension.

It would seem that my method would expose to a lot of oxygen, but I have never noticed it in the taste, nor have any of the BJCP judges in my homebrew club. However, I really like the simplicity of Day_trippr's system in this thread.
 
I started cold crashing when I started kegging last year. My first NON-cold crashed brew I kegged had a good 2-3 pints of yeast trub in it and was super cloudy.

After that experience, and my usual "HBT-research-to-fix-a-mistake-I-could-have-avoided-in-the-first-place" routine, my cold crashed batches usually have no more than 1/2 a pint of trub (including the sanitizer I let sit in the tap line until the first pull of the keg) and, my brews are much more clear now.

During crashing, I replace the airlock with a vinyl tube and an in-line HEPA air filter inserted in the other end. That way, air can come in as it cools and at least the air that enters will have hopefully less "stuff" in it.

The "crash tube" as I call it, is also long enough to snake down near the bottom of my freezer which, at this point, is usually filled with CO2 anyways from the fermentor going for 2 weeks.
 
I don't really care about "clear beer" but ...

The stuff that makes the beer cloudy also can have a negative affect on flavor, and I'll be you care about that. E.g., I hate the flavor of yeast in my beer - I don't drink hefe's.

I happen to also like the look of a clear beer, especially pilsners, which I make a lot. Hoppy beers are usually going to have some cloudiness from the monster dryhopping I do :rockin:
 
After experiencing the suck back mentioned earlier, and diluting my brew with Starsan, this is what I do. I fill the ziplock with co2 and bypass the airlock. The co2 gets pulled into the carboy during the cold crash. Works for me.

IMG_1521.jpg
 
For those using blow off tubes, wouldn't one solution be to lengthen the tube so that the pressure/headspace CO2 volume change due to the temperature drop so that it only sucks back the CO2 that's in the tube?

If the liquid in the blow off container sits lower than the height of the liquid in the fermenter, a reverse siphon cannot occur.
 
There is crashing your beer to get the yeast to settle a little faster and then there is Cold Crashing. Cold crashing means dropping your beer down to the low 30s to get the proteins that produce chill haze to drop out. It can be used in combination with finings or without.
 
I cold crash in my chest freezer fermentation chamber. I typically put a layer of CO2 in the fermenter when I dry hop, and since it is heavier than O2, I'm not too worried about a little O2 getting sucked in during cold crash. I also put ball valves in my fermenter buckets and by cold crashing, the trub packs down nice and tight in the bottom so I can transfer right into the keg without getting any sludge
 
Using a blow off tube with cold crashing is the largest source of "one gallon of sanitizer sucked into my beer" posts.



A one piece "s style" airlock allows air to pass without sucking the sanitizer inside. A blow off tube will likely suck sanitizer in........ It can also start a reverse siphon and suck all the sanitizer out of your catch container.


Yep been there done that! Sucked all the sani back on a batch once. Sad day
 
If the "suck back" is the main concern why don't use solid carboy stopper?
 
After experiencing the suck back mentioned earlier, and diluting my brew with Starsan, this is what I do. I fill the ziplock with co2 and bypass the airlock. The co2 gets pulled into the carboy during the cold crash. Works for me.


Brilliant!!!
 
If the "suck back" is the main concern why don't use solid carboy stopper?

because you run the risk of collapsing your fermenter or sucking the stopper into the carboy, whichever gives first. When you cool down gases the pressure drops, which creates a vacuum in a sealed container
 
After experiencing the suck back mentioned earlier, and diluting my brew with Starsan, this is what I do. I fill the ziplock with co2 and bypass the airlock. The co2 gets pulled into the carboy during the cold crash. Works for me.


I did something very similar to yorkeken and his ziplock bag - only I used one of those Mylar balloons that seems to keep inflated for weeks on end (I was afraid the CO2 would leak out the baggie). Worked like a charm, but a lot more hassle than the baggie, which I'll try next. No O2 concerns and easy peasy cold crashing.

Also, a previous poster mentioned that sanitizer would not "suck" back into the fermenter during cold crashing if the level of the sanitizer was below that of the fermenter. While this may be true if you have a massive blow off tube, for those of us who use 1/2" blow off tubes, I would like to forwarn that it was demonstrably not true for my brew buddy who lost more than one batch due to this oversight. Clearly the gravity syphon principle gets defeated by the negative pressure in the top of the fermenter. Even worse is when the sanitizer mix gets overwhelmed and diluted by blow-off trub and then what gets sucked in is no longer sanitizer but, in fact, a rather unsanitary yeasty mix of who knows what that likely has been picking up nasties from the refrigerator.
 
Also, a previous poster mentioned that sanitizer would not "suck" back into the fermenter during cold crashing if the level of the sanitizer was below that of the fermenter.

I started to comment on that same post, but then notice that his exact words were "reverse siphon" and it is true that it won't work like a siphon. It just works like a straw.
 
If you use a one piece airlock or a blow-off tube, the air and liquid will not be pulled into the fermentator. I always cold crash.

-Joe
This is not true.... I have seen a blow off tube suck back nearly a quart of liquid in a cold crash from 70 degrees to 30 degrees.

Sorry I should have read on to see others have already addressed this mis-information.
 
I use a 1" blowoff tube on my glass 6 gal. carboy and the reason I now use the co2/ziplock method is because I did experience liquid suck back and it wasn't pretty. I know that if I didn't use as much starsan, the liquid wouldn't have made it all the way up and into my brew but even at that, suction is created and when removing the blowoff tube, o2 would go rushing in to equalize the pressure.
 
Come on everybody. Quit using all those things that can create problems for you. Use a fermenter, that is large enough to contain the kreusen ,with a simple airlock. If you are cold crashing, you have some sort of fermentation chamber. If it's a chest freezer it should be full of co2. So there's little chance of getting o2 into your brew. If you use anything else, don't worry about it because there's a layer of co2 in your fermenter that will block the o2. When you turn down the temperature, empty the airlock. Done! By the way, a little gelatin in the keg or if you're bottling, in the fermenter, will give you a crystal clear brew. K.I.S.S.
 
don't worry about it because there's a layer of co2 in your fermenter that will block the o2.

This has been proven to be false. Fortunately, or else we would be able to breathe right now, any turbulence mixes air. I'm not saying it will ruin your beer, but it just doesn't 'layer' like homebrewers believed for years.
 
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