Cold crashing in glass carboy

[Art2019]

The idea is that you install the tubing and blowoff jar at the start of fermentation and keep it there during the entire fermentation process. The CO2 generated will purge the tubing of almost all its air. Then when it's time to cold crash, the reduction in pressure will draw back CO2 stored inside the tube.

It will also draw some of the liquid up from the blowoff jar, but unless you have a huge amount of headspace, the liquid shouldn't reach your fermenter, due to the large volume inside the tubing.

I was thinking about that but If i did this, then I wouldn't be able to use my thermowell for temp control. This has been one of the reasons for using my chest freezer. Guess, I could just tape probe on carboy like I've seen.

 

[shoengine]

Increase hose length, reduce hose ID, and use one of these?

https://www.morebeer.com/products/hood-thermowell-smooth-neck-carboys-15.html

 

[Art2019]

Increase hose length, reduce hose ID, and use one of these?

https://www.morebeer.com/products/hood-thermowell-smooth-neck-carboys-15.html

I already have one of those. But the ID will be smaller so i'll need to use a longer hose than 4', right?
The orange cap is what I'll be using for my transfer.

 

[shoengine]

If you are relying on the air space in the hose, you'd have to lengthen the hose for the corresponding loss of volume when reducing the inner diameter. All of the requirements for volume is calculable with the variables being your headspace, the volume of gas in the liquid, and the temperature you are crashing to. With that said, I have no idea how to do that myself.

For what it is worth, I don't know the sealing capability of those caps when negative pressure is involved. I did have one blow off of my carboy years ago when the airlock plugged, so they do have the capability to seal with positive pressure.

 

[mac_1103]

deleted

 

[InspectorJon]

The Mylar balloon idea has been discussed. I use one myself. Just in case someone didn’t think about this, there is a one way valve inside the balloon that has to be disabled. I use a long nose pliers to reach inside and pull it out.

 

[mac_1103]

the ID will be smaller so i'll need to use a longer hose than 4', right?

Yes, but that's going to end up being a lot of tubing. Since it's not an option for this batch anyway, one of the other solutions would probably be easier.

 

[Art2019]

Yes, but that's going to end up being a lot of tubing. Since it's not an option for this batch anyway, one of the other solutions would probably be easier.

True, but I could size up starting from adding tube to top of orange cap, then add a larger tube for other half of that.

 

[IslandLizard]

May I suggest a different route?

Transfer the beer as cleanly as you can to a keg, leaving the trub behind. Then cold crash it in the keg under some headspace pressure. Once clear, either serve directly or transfer to a serving keg.

At the end of the cold crash there will be a fairly compacted yeast/trub cake on the bottom of the keg. You can use a floating dip tube to serve the clear beer directly (from the top).

Or transfer the clear beer, either with a floating or regular (long) dip tube. In the last case, (with a regular, long diptube) first blow out the trubby beer from the bottom until it flows clear before transferring.

 

[JohnDBrewer]

If you a vacuum packer, those plastic bags work well.

 

[Art2019]

May I suggest a different route?

Transfer the beer as cleanly as you can to a keg, leaving the trub behind. Then cold crash it in the keg under some headspace pressure. Once clear, either serve directly or transfer to a serving keg.

At the end of the cold crash there will be a fairly compacted yeast/trub cake on the bottom of the keg. You can use a floating dip tube to serve the clear beer directly (from the top).

Or transfer the clear beer, either with a floating or regular (long) dip tube. In the last case, (with a regular, long diptube) first blow out the trubby beer from the bottom until it flows clear before transferring.

Could cold crash in keg with a floating dip tube. Better option.
So, there won't be issues in keg being sealed with cold crashing?

 

[shoengine]

You can put gas on it at 1 or 2 psi while it is crashing to keep positive pressure. That's what I do on my unitank.

 

[kurds_2408]

If you a vacuum packer, those plastic bags work well.

I’ve used this method for my one gallon experimental batches since my one gallon fermentor can’t handle pressure. Definitely recommend it.

 

[IslandLizard]

So, there won't be issues in keg being sealed with cold crashing?

As @shoengine said, you could put gas on it at a low pressure. Make sure the keg doesn't leak at that low pressure or it could drain your tank.

I usually just fill the headspace with 15-20 psi CO2 (and making sure it's sealed).
Since the headspace CO2 will be slowly absorbed by the beer, carbonating it a little until a pressure equilibrium is reached, you could bring it back up a few times if needed.

I do the same when keg conditioning in my utility room.

 

[Art2019]

You can put gas on it at 1 or 2 psi while it is crashing to keep positive pressure. That's what I do on my unitank.

Is the FermaZilla pressure building kit considered a unitank? I don't want to get extravagant, just want a nice brew

 

[shoengine]

Is the FermaZilla pressure building kit considered a unitank? I don't want to get extravagant, just want a nice brew

I believe what makes something a unitank is if you can ferment and serve from the same vessel, so any corny keg can be one with the proper equipment. For the pressure kit from Williams Brewing's website:

 

[Unicorn_Platypus]

There is another way. Use a spunding valve to ensure 24 psi at end of active fermentation. After cold-crashing the pressure in fermentor will still be 12psi. Not only did you avoid O2, your beer is already carbonated.

Lots more to this, but that is an option for some other time.

bad/dangerous idea on a carboy as it can't hold pressure. If it's fermzilla or keg fermentor, no issue.

 

[Unicorn_Platypus]

there's no real reason to cold crash in the carboy if you are kegging anyway. The beer will naturally cold crash in the keg. If you use a floating diptube (e.g. flotit or CBDS) then the beer can crash in the keg as it conditions and you will only pull clear beer from the top.

If you have a traditional diptube, then you will pull junk. Switch to floating diptubes in all your kegs like I do

 

[Unicorn_Platypus]

I believe what makes something a unitank is if you can ferment and serve from the same vessel, so any corny keg can be one with the proper equipment. For the pressure kit from Williams Brewing's website:

View attachment 858938

a fermzilla is basically a unitank, but since its PET its not recomended for long term storage. Transfering to a keg is the way to go, but the fermzilla is great for closed transfers and pressurized fermentations.

 

[shoengine]

bad/dangerous idea on a carboy as it can't hold pressure. If it's fermzilla or keg fermentor, no issue.

Haha, if the guy can get a carboy cap to resist 288 pounds, I'm all for it!

 

[Art2019]

bad/dangerous idea on a carboy as it can't hold pressure. If it's fermzilla or keg fermentor, no issue.

Wasn't going to

a fermzilla is basically a unitank, but since its PET its not recomended for long term storage. Transfering to a keg is the way to go, but the fermzilla is great for closed transfers and pressurized fermentations.

I already transfer to keg.

 

[mashdar]

I'd be wary of intentionally increasing plastic suface area unless it's a known-good O2 barrier (e.g. mylar, PET, EVAbarrier). Doubling the blowoff surface area doubles the rate of diffusion, and IIRC the PVC tubing has rather poor O2 performance already. (Isn't this why people switched to EVAbarrier?)

Reducing suckback by accepting high diffusion for weeks may not be productive.

Food for thought; empirical results may say otherwise.

 

[redrocker652002]

I will admit I have not read all the posts, but the ones that said transfer to a keg and cold crash in that is what I do. My bucket fermenter usually sits at the mid range of the yeast. Once done, usually after two weeks, I close transfer into my keg, put it in my kegerator and set the temp at around 35 or so and hook up my gas line. Leave it for a week or two and then pull a pint a day until I see it is carbonated and off I go.

 

[Art2019]

I'd be wary of intentionally increasing plastic suface area unless it's a known-good O2 barrier (e.g. mylar, PET, EVAbarrier). Doubling the blowoff surface area doubles the rate of diffusion, and IIRC the PVC tubing has rather poor O2 performance already. (Isn't this why people switched to EVAbarrier?)

Reducing suckback by accepting high diffusion for weeks may not be productive.

Food for thought; empirical results may say otherwise.

It's glass not plastic.
I've decided to transfer to keg, then cold crash.

 

[mac_1103]

It's glass not plastic.

He was talking about the tubing.

 

[Bramling Cross]

To give you an idea of how much volume you need to perform an anti-suck operation, here's my large ale rig designed to cope with 72F TG to 38F crashes on a 7-gal fermenter. Those are big 1qt Ball jars. In the first photo, you can see the rig set up and ready to be attached to my fermenter. In the second photo you can see the the rig post-fermentation following a crash from 68F to 38F. As you can see, the full volume of Star San has been pulled from the first jar into the second. Granted, a lot of the transferred volume was pulled as a result of a siphon effect started by the crash, but it gives you an idea regarding the volumes involved in the process.

My lager rig is much smaller and uses standard Ball jars because there's less volume involved in a 58F-38F crash.

When I fermented in glass, I preferred crashing in a dedicated keg. A 6-gal keg is a really useful tool for crashing, fining, and dry hopping sans O2. Best of all, that 6-gal keg will ensure you still get a complete 5-gal fill in your serving keg.

#1, Pre-fermentation anti-suckback rig

#2 Same rig, post fermentation

 

[mashdar]

Looking at a keg carb chart at 1psig, it goes from 0.88 vols at 65F to 1.75 vols at 32F. Doesn't that imply you're going to need ~4.35 gallons of STP CO2 (plus ~7% of headspace volume) to reach equilibrium for a 5 gallon batch?

Granted, you might not reach equilibrium with a short crash, but I would think the time curve would be asymptotic and you'd need a large fraction of that.

What am I missing?

(I'm always surprised when I need 15+psi spund to maintain 3psi during crash. That's with ~ 2:1 beer to headspace.)

edit: For a more restrained example, from 60F to 40F would appear to need 0.46 vols, or 2.3 gals CO2 at STP.

 

[InspectorJon]

I have a 5 gallon carboy. I use a smiley face mylar balloon. It is kind of a standard size party balloon. I typically have around 1 gallon of head space in the carboy. Cold crashing from 70F to 32F uses up what looks like one third to one half the CO in the balloon.