Cold Crashing

Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum

Help Support Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum:

Texas_Red

Member
Joined
Jan 8, 2015
Messages
22
Reaction score
11
Location
St Louis
I have an IPA in the fermenter that I will be kegging at the end of the week. I have not cold crashed in the past but like the idea of having a much clearer beer. I understand just putting my fermenter in the fridge will suck in air and risk oxygen getting in which we all know is bad. I have also read about cold crashing in the keg. So what is the process there? Do I just transfer to keg, purge with CO2, and put in the fridge without pressurizing the keg for a day or 2?
 

Dr_Jeff

Supporting Member
HBT Supporter
Joined
Dec 13, 2011
Messages
2,014
Reaction score
1,545
Location
Henagar, Alabama
I have an IPA in the fermenter that I will be kegging at the end of the week. I have not cold crashed in the past but like the idea of having a much clearer beer. I understand just putting my fermenter in the fridge will suck in air and risk oxygen getting in which we all know is bad. I have also read about cold crashing in the keg. So what is the process there? Do I just transfer to keg, purge with CO2, and put in the fridge without pressurizing the keg for a day or 2?


Go ahead and hook up the gas, let the carbonation process start.
 

Dr_Jeff

Supporting Member
HBT Supporter
Joined
Dec 13, 2011
Messages
2,014
Reaction score
1,545
Location
Henagar, Alabama
Seems to me that everyone cold crashes when kegging by just putting the keg in the keezer , but I'm new to home brewing.
Most do.
One ends up with a bit of sediment in the first pour and it is good until the kegs kicks, unless the keg gets moved.

If the beer can be cold crashed in the fermenter, one ends up with less sediment in the keg.

It really depends on what equipment you have and the capabilities of said equipment.
 
OP
OP
T

Texas_Red

Member
Joined
Jan 8, 2015
Messages
22
Reaction score
11
Location
St Louis
OK so I guess just the act of kegging it handles the cold crash. So I will just end up with a little sediment on my first pour. No big deal. Appreciate the replies.
 

spittiz

Well-Known Member
Joined
Jun 14, 2021
Messages
56
Reaction score
160
Location
Finland
To me, cold crashing means cold crashing in the fermenter, if you've kegged the beer I don't know why you wouldn't hook up the CO2 at the same time, and when you do, it's conditioning at that point IMO (not cold crashing), whatever the temp might be.

When cold crashing in the fermenter, you get less particles in your keg = less sediment. But yeah, if you just toss a fermenter with an airlock into a fridge you will have a lot of suck back = oxygen gets in (and possibly some of your airlock solution), so it's not good. The solution is to have a closed fermenter that can handle a little pressure, e.g. a Fermzilla, I use the All-rounder myself. When I want to cold crash, I swap out the airlock to a ball-lock post and CO2 purge the headspace a few times for good measure, leave a slight pressure in the vessel and then do the cold crash, and since the fermenter is air-tight at this point, no oxygen gets in.

If you don't have a pressure-capable fermenter and don't plan on getting one, some people use mylar balloons attached to the airlock during the fermentation, to capture co2. Then when you cold crash, the pressure drop just ends up sucking co2 back from the balloon instead of oxygen. I tried it a couple of times myself, and I suppose it worked all right, but I much prefer to just use a proper fermenter. The balloon method is mentioned here among other places.
 

InvertedPilot

Supporting Member
HBT Supporter
Joined
Nov 12, 2022
Messages
18
Reaction score
8
Location
Texas , Houston
I have cold crashed my fermentor at 34 F for 5 days prior to kegging. The problem is that when you cool the fermentor it tends to create a vacuum that pulls fluid from the air lock. The only way I can think to correct this install a blanketing regulator and CO2 at 0.25 PSI The regulator is connected to a sealed 1 gallon catch can. Where 1/4 PSI regulator is connected at the top and and the fermentor is also connected from the top. Blow off falls to the bottom of the catch can into 16oz of Star san water. If the fermentor creates a vacuum the regulator will feed CO2. The fermentor can hold 75 gallons. A ranco controller keeps the freezer converted to fermentor at 68F during fermentation.
 

Attachments

  • 2013-09-12 01.26.56.jpg
    2013-09-12 01.26.56.jpg
    654.2 KB · Views: 0
  • IMAG0006.jpg
    IMAG0006.jpg
    1.1 MB · Views: 0
  • IMAG0726.jpg
    IMAG0726.jpg
    167 KB · Views: 0
  • IMAG0015.jpg
    IMAG0015.jpg
    1.3 MB · Views: 0

day_trippr

Structural Duct Tape Applications Engineer
Joined
May 31, 2011
Messages
39,325
Reaction score
22,620
Location
Stow, MA
I do nearly that - I use a cheap barbecue grill regulator to down-regulate CO2 pressure to a reliable .5 psi, connected to an otherwise sealed fermenter.
I wouldn't cold-crash anything without it, and especially not my neipas :)

Cheers!
 

catalanotte

Well-Known Member
Joined
Jul 30, 2014
Messages
324
Reaction score
220
I typically don’t cold crash and just let things settle naturally in the fermenter then again in the keg. However, I have rushed beers to keg that haven’t cleared enough in the fermenter and a lot of sediment is expected. I’ll chill the keg for 2-3 days then pressure transfer into another keg through the liquid line. This provodes clear beer without oxygen exposure. It is a bit of extra work with the second keg, but only used when needed.
 

dmaxweb

Well-Known Member
Joined
Sep 14, 2006
Messages
103
Reaction score
32
Location
Williamsburg
I do nearly that - I use a cheap barbecue grill regulator to down-regulate CO2 pressure to a reliable .5 psi, connected to an otherwise sealed fermenter.
I wouldn't cold-crash anything without it, and especially not my neipas :)

Cheers!
What about cold crashing fermenter with airlock removed and charge a corny with CO2 to 1 PSI attached?. I don't want to rely on fermenter being 100% airtight and losing a tank of CO2.
 

tracer bullet

Supporting Member
HBT Supporter
Joined
Aug 10, 2020
Messages
1,784
Reaction score
1,545
Location
Minnesota
This is a pretty clever device as well. I won't say if it's "worth" the cost but it does indeed work (I went ahead and bought one).

Basically CO2 pushes out of the fermenter through the first jar, then into the 2nd. If there's suck-back, it goes fromt he 2nd jar into the 1st one, while CO2 from that 1st jar is pulled back into the keg. If that made sense.

 

palmtrees

Well-Known Member
Joined
Jul 11, 2013
Messages
214
Reaction score
216
Location
Atlanta
I do think cold crashing in the fermenter is valuable (if you can do it without oxygen ingress), not just because you get less sediment in the keg but also because you generally get a higher yield. When I cold crash, the yeast and trub and hips form a much more tight & compact layer than when I let them settle at fermentation temps. So not only do I transfer less sediment, but I end up being able to pull more beer out of the fermenter and into the keg.
 

dmaxweb

Well-Known Member
Joined
Sep 14, 2006
Messages
103
Reaction score
32
Location
Williamsburg
You could try one of these. Basically an easier to use and more reliable version of the mylar balloon.
Not to knock that product but it seems like the same concept except using a corny keg instead a bladder. Pressure in the fermenter exceeding the pressure in the keg would push CO2 back into keg. This would be for post-active fermentation cold crash prior to fining and kegging so likely no excessive pressure. Again, not to disparage that product but in the long run a stainless corny will outlast a bladder. Plus, I have a spare low pressure regulator.
 
Last edited:

mac_1103

Well-Known Member
Joined
Sep 15, 2022
Messages
154
Reaction score
206
Location
Virginia
Yeah, if you've got extra kegs lying around and the extra space to fit your fermenter and keg into whatever you're crashing in, knock yourself out. But the point of these other approaches/devices is that you don't need much CO2 or any pressure to satisfy the vacuum created in the FV during cold crashing, so why not use something small and cheap? The NorCal kit seems a bit pricey to me for what it is, but you can make your own with a half-inch drill bit and some grommets.
 

dmaxweb

Well-Known Member
Joined
Sep 14, 2006
Messages
103
Reaction score
32
Location
Williamsburg
Yeah, if you've got extra kegs lying around and the extra space to fit your fermenter and keg into whatever you're crashing in, knock yourself out. But the point of these other approaches/devices is that you don't need much CO2 or any pressure to satisfy the vacuum created in the FV during cold crashing, so why not use something small and cheap? The NorCal kit seems a bit pricey to me for what it is, but you can make your own with a half-inch drill bit and some grommets.
If I understand how the NorCal kit works, I think I need more than a quart volume of CO2 at best for a 15 gallon fermenter. If the airlock has stopped bubbling and SG has been constant for a week, would the fermenter even produce a qt. of CO2 when cold crashing starts?
 

mac_1103

Well-Known Member
Joined
Sep 15, 2022
Messages
154
Reaction score
206
Location
Virginia
You hook the device up at the start of fermentation so you capture CO2 during active fermentation to use later during cold crashing. The kit doesn't include the jars. You can use any size you want.
 

dmaxweb

Well-Known Member
Joined
Sep 14, 2006
Messages
103
Reaction score
32
Location
Williamsburg
Since I'm past active fermentation, I'll just charge a 3 gallon corny with 1PSI CO2. I have everything else I need on hand. Thanks for your input.

I see you are also in Virginia.
 

DVCNick

Well-Known Member
Joined
Sep 12, 2018
Messages
669
Reaction score
219
Nothing against messing with balloons, etc, and that works for some people for sure, but I do one of two things:

-If I know I have a beer that is going to have a TON of crud in it that I want to cold crash out before transferring to serving keg, I use a Fermentasaurus snub nose, and can easily either spund it with a few points to go or hit it with some bottle gas at the end. It fits in my chest freezer or kegerator, has a floating dip tube, is super easy to cold crash with zero air ingress, and isn't even that bad to clean.

-Alternately, I just don't cold crash in the fermenter. As mentioned above, you are cold crashing in the keg once it goes in your kegerator anyway. If you aren't going to have really excessive crud in the bottom, I just pour off the first couple pints or so, and it is pretty even-keel from there until the keg is almost empty... of course depending on the exact yeast, etc.
 

dmaxweb

Well-Known Member
Joined
Sep 14, 2006
Messages
103
Reaction score
32
Location
Williamsburg
I plan on doing a closed CO2 transfer off the yeast cake in the primary directly into a CO2 purged secondary fermenter in the lager fridge (temp contolled using A419 with sensor in fermenter thermowell). Hook up my corny charged with 2 PSI or so and let it sleep for a while before fining, if necessary, and closed transfer to kegs. I have all the stuff so no further expense. I find these DIYs almost as enjoyable as drinking the final product..

First up and ready is a Belgian Dubbel currently in the primary starting 1.072 and ending 1.013. Should be a fun project!
 

tld6008

Master of Nothing
HBT Supporter
Joined
Aug 24, 2017
Messages
431
Reaction score
178
Location
Pensacola
You hook the device up at the start of fermentation so you capture CO2 during active fermentation to use later during cold crashing. The kit doesn't include the jars. You can use any size you want.
All depends on the headspace in the fermenter. I would definitely use larger jars. The bag method allows all the volume in it to be used as it collapses unlike a rigid container.
 

Arthur Davila

New Member
Joined
Feb 20, 2019
Messages
1
Reaction score
0
Location
São Paulo
I have an IPA in the fermenter that I will be kegging at the end of the week. I have not cold crashed in the past but like the idea of having a much clearer beer. I understand just putting my fermenter in the fridge will suck in air and risk oxygen getting in which we all know is bad. I have also read about cold crashing in the keg. So what is the process there? Do I just transfer to keg, purge with CO2, and put in the fridge without pressurizing the keg for a day or 2?
Have you tried a dmfit valve on the blow off scheme? They have two options, open and close or anti-return
 

dmaxweb

Well-Known Member
Joined
Sep 14, 2006
Messages
103
Reaction score
32
Location
Williamsburg
All depends on the headspace in the fermenter. I would definitely use larger jars. The bag method allows all the volume in it to be used as it collapses unlike a rigid container.
If the rigid container (corny in my example) is low pressurized with CO2, it's the same as a bladder pressurized by capturing fermentation CO2. With the bladder, when it's gone, it's gone vs. a keg that can maintain pressure.

I know I'm over complicating this whole thing but I'm retired, have the equipment and looking for some to do.

Edit: I don't think the volume of headspace has measurable significance by itself. It's the contraction of the liquid that increases the headspace thereby lowering the PSI of the CO2 blanket. Once below outside PSI, negative pressure in the fermenter causes suck-back.
 
Last edited:

mac_1103

Well-Known Member
Joined
Sep 15, 2022
Messages
154
Reaction score
206
Location
Virginia
You are over complicating it, especially since you have the kegs, the space and the time.

I've used the cold crash guardian a few times. The large bladders hold 2 1/2 gallons. Cold crashing a 6/12 6 1/2 gallon fermenter never seems to use more than about a third of the gas, and usually quite a bit less. Then again, I'm taking it from 65F to 40F. I'd expect to need more if I was going from 80 to 30.
 

dmaxweb

Well-Known Member
Joined
Sep 14, 2006
Messages
103
Reaction score
32
Location
Williamsburg
Have you tried a dmfit valve on the blow off scheme? They have two options, open and close or anti-return
If fermentation has stopped before cold crashing, outside air will be drawn in or create a vacuum, depending on how the valve is set as the beer contracts. If the valve is closed or anti-return, outside air will be drawn in when you open the fermenter drain valve. You could hook up co2 to the valve before opening it. If using a plastic bucket for a fermenter, I don't know what the vacuum would do with the valve closed. Maybe suck in the stopper?

As a side note I've always used cheap vodka in air lock during fermentation and Star San in a jug if using a blow off tube.
 
Joined
Jan 19, 2023
Messages
23
Reaction score
25
Location
New Orleans La
I started kegging a few months ago and started trying to transfer from a "cold crashed" Fermenter to the keg without introducing too much oxygen. After fermentation is complete I quickly swap out the airlock with another one I came up with by rigging up a piece of silicone tubing from my airlock to an old plastic bucket drain valve. I can see the FV top being sucked in after 2 days Cold crashing. No air suck back or leaks and holds well.
I then take the fermenter out and hook up CO2 to the plastic valve and turn on the CO2 about 2-3 psi…open the valve until the inverted fermenter top starts to rise and pressurize.
I leave the CO2 on and then open my fermenter’s drain valve to a purged CO2 keg which drains the fermenter pretty good. May not be 100% oxygen free but better than an open fermenter I guess.
(Can also add CO2 anytime during cold crashing) through the plastic valve. I Star-San everything before starting). Seems to be working well for me so far. I’ll keep experimenting.
‘Cheers
 

Attachments

  • 8B7A61FF-F82C-4E49-80C8-8A11522918B1.jpeg
    8B7A61FF-F82C-4E49-80C8-8A11522918B1.jpeg
    2.3 MB · Views: 0
Last edited:

tracer bullet

Supporting Member
HBT Supporter
Joined
Aug 10, 2020
Messages
1,784
Reaction score
1,545
Location
Minnesota
I came up with by rigging up a piece of silicone tubing from my airlock

:) Funny, I've done similar, and seen others do it. Lots of people have the same idea. Thoguhts for you:

* There's a chance your silicone stopper will get sucked into the fermenter. No guarantees, and I can't give you a % chance, but I'm positive that it exists.
* Silicone is pretty awful for keeping oxygen out. Shorter is better here. You'll have some amount of O2 entering 24/7 through it.
 
Joined
Jan 19, 2023
Messages
23
Reaction score
25
Location
New Orleans La
:) Funny, I've done similar, and seen others do it. Lots of people have the same idea. Thoguhts for you:

* There's a chance your silicone stopper will get sucked into the fermenter. No guarantees, and I can't give you a % chance, but I'm positive that it exists.
* Silicone is pretty awful for keeping oxygen out. Shorter is better here. You'll have some amount of O2 entering 24/7 through it.
Thanks for the advice. Wasn’t aware that oxygen permeated silicon easily. I guess I’ll just keep "bumping" the fermenter with CO2 bursts to keep it equalized somewhat before kegging. (I would think if O2 is getting inside that the lid wouldn’t be inverted showing a good vacuum seal. (Maybe I’ll explore different tubing) any ideas of a better tubing to keep O2 out ?
also I don’t think there’s anyway this stopper will go through the lid As it’s much larger at the top side.
thanx again
Cheers
 
Last edited:

Closet Fermenter

Supporting Member
HBT Supporter
Joined
Apr 12, 2022
Messages
90
Reaction score
91
I put a weldless triclamp bulkhead on the lid of my fermenter. I attached a ball lock tapping head on this. It makes it easy to attach a bubbler or blow onto the gas post. It would also be easy to attach CO₂ during cold crash. I use it primarily for closed transfers to my kegs: gas to gas, liquid to liquid hoses with connectors.
 

Attachments

  • E7990FD1-E103-4B01-B5BC-2F4ECF15CCAB.jpeg
    E7990FD1-E103-4B01-B5BC-2F4ECF15CCAB.jpeg
    136.4 KB · Views: 0
  • BECE14AD-AF59-4905-9EFD-84DF5463B26D.jpeg
    BECE14AD-AF59-4905-9EFD-84DF5463B26D.jpeg
    538 KB · Views: 0
Joined
Jan 19, 2023
Messages
23
Reaction score
25
Location
New Orleans La
I put a weldless triclamp bulkhead on the lid of my fermenter. I attached a ball lock tapping head on this. It makes it easy to attach a bubbler or blow onto the gas post. It would also be easy to attach CO₂ during cold crash. I use it primarily for closed transfers to my kegs: gas to gas, liquid to liquid hoses with connectors.
Thanx.. looks much better than my "rig-up". Wasn’t aware of these fittings. Guess I can figure out the transfers and bubbler hook ups. Will definitely look into this. 👍🏼
 
Top