Cold crashing in glass carboy

[Art2019]

I want to try cold crashing my brew in glass carboy & have a single airlock.
I read to fill water up to max fill line on airlock & I'll be fine. I've also read to attach a blowoff hose & insert into water to prevent add'l air from entering.

Is one way better than the other, or another preferred method? It seems like, unless the blowoff tube is filled with water, air would still have a chance to enter carboy, right?

 

[MaxStout]

I want to try cold crashing my brew in glass carboy & have a single airlock. I'm reading it would be best case would to use a twin bubble airlock.

Is there a way to get around the twin airlock for this? I have a blowoff tube in a container when it was fermenting so should I just keep this tube in the same container to prevent excess air being sucked in carboy?

The blowoff tube will draw liquid into the fermenter when you cold-crash. The only way to prevent O2 from being drawn in is to have some reservoir of inert gas like CO2 connected to the fermenter. Something like this works great.

 

[mac_1103]

I don't think a twin bubble airlock will prevent suck back. The blow off tube in a container of water or starsan will prevent air from being sucked back, but only because the water or starsan will get sucked back instead. Is this beer already fermented and ready to crash now? Because if not, there are lots of things you can hook up to the fermenter at the start to solve this problem in advance.

 

[Art2019]

I don't think a twin bubble airlock will prevent suck back. The blow off tube in a container of water or starsan will prevent air from being sucked back, but only because the water or starsan will get sucked back instead. Is this beer already fermented and ready to crash now? Because if not, there are lots of things you can hook up to the fermenter at the start to solve this problem in advance.

Yes, it's ready to cold crash. I want to transfer to keg in a couple of days. Any suggestions without having to order something?

 

[mac_1103]

Any suggestions without having to order something?

Get a mylar balloon; fill it with CO2; attach it to the blow off tube.

 

[Art2019]

Get a mylar balloon; fill it with CO2; attach it to the blow off tube.

Don't have that. How about if I just fill blowoff tube with liquid. Is about 3 ft long.

 

[mac_1103]

No place where you can buy a balloon?

Three feet of 1/2" ID tubing holds what, maybe four ounces? Depending on the current temperature, crash temperature, head space volume and how long you crash, you could easily suck back a lot more than that. See this old post for example.

 

[BongoYodeler]

If it were me, at this point in time, if you can't get a mylar balloon as @mac_1103 suggests, I probably wouldn't cold crash. Just transfer the beer into the keg or bottling bucket at the current temperature and carry on. Perhaps not ideal, but better than sucking in oxygen and/or sanitizer solution.

 

[Art2019]

No place where you can buy a balloon?

Three feet of 1/2" ID tubing holds what, maybe four ounces? Depending on the current temperature, crash temperature, head space volume and how long you crash, you could easily suck back a lot more than that. See this old post for example.

It'll be a 30 mile commute for a milar baloon. I can always postpone the crash until I get something like that

 

[shoengine]

Has your fermentation reached terminal gravity?

 

[bkboiler]

there are some setups with more than one mason jar to eliminate suck back and avoid oxygen ingress...a few places have them but NorCal brewing solutions springs to mind ..you may be able to rig something kinda like that but if your beer is already done fermenting you may have to rig up another way to generate CO2....sugar water and a pinch of bread yeast in the first or second mason jar? Not sure how something like that would work, imagine getting the balloon at this point is probably easier than rigging two rigid accumulators

There are several townships near me where mylar is outlawed. A lot of people would take them to the beach, let them go and then they'd litter the ocean or nearby beaches when they pop and fall back down...have to drive to get them or order online....

 

[Art2019]

Has your fermentation reached terminal gravity?

It's been almost 3 weeks so, yes, I would say so. It usually takes a week for it to finish. This is the longest time is had it in carboy without transferring.

 

[mac_1103]

This is the longest time is had it in carboy without transferring.

Three weeks in the fermenter hasn't hurt your beer, and another few days won't hurt it either. Assuming that it is well sealed of course, and that blow off tube stays submerged. Especially since it's in glass (as opposed to plastic that is at least somewhat oxygen permeable).

 

[passedpawn]

The blowoff tube will draw liquid into the fermenter when you cold-crash. The only way to prevent O2 from being drawn in is to have some reservoir of inert gas like CO2 connected to the fermenter. Something like this works great.

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.

 

[Art2019]

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.

Maybe for my next batch. But for my carboy, i won't exceed more than 2 psi. Don't care to risk it cracking.

 

[mac_1103]

Use a spunding valve to ensure 24 psi at end of active fermentation.

Not in a carboy.

 

[Art2019]

Three weeks in the fermenter hasn't hurt your beer, and another few days won't hurt it either. Assuming that it is well sealed of course, and that blow off tube stays submerged. Especially since it's in glass (as opposed to plastic that is at lease somewhat oxygen permeable).

Agreed.

 

[passedpawn]

Not in a carboy.

Right. I use fermzilla all-rounders.

 

[MaxStout]

No place where you can buy a balloon?

Three feet of 1/2" ID tubing holds what, maybe four ounces? Depending on the current temperature, crash temperature, head space volume and how long you crash, you could easily suck back a lot more than that. See this old post for example.

For next time, there is another option. Buy a length of the largest plastic tubing you can fit inside the mouth of the carboy. I'm thinking maybe an inch ID or so. Three or 4 feet of that will hold a lot of CO2 from primary, and perhaps be too much volume for the liquid to suck all the way back at cold crash.

 

[Art2019]

For next time, there is another option. Buy a length of the largest plastic tubing you can fit inside the mouth of the carboy. I'm thinking maybe an inch ID or so. Three or 4 feet of that will hold a lot of CO2 from primary, and perhaps be too much volume for the liquid to suck all the way back at cold crash.

Will need to think any that one.
Anyway, anticipating a cold crash, the temp was down to 54F. Hope I didn't spoil it. I'm having it increase back to where it was at 66F.

 

[mac_1103]

Three or 4 feet of that will hold a lot of CO2 from primary, and perhaps be too much volume for the liquid to suck all the way back at cold crash.

If I'm doing this right, 40 inches of 1 inch ID tubing has a volume of a little more than a pint, which should be enough to handle a 30F drop for a few days.

 

[mac_1103]

anticipating a cold crash, the temp was down to 54F. Hope I didn't spoil it.

That shouldn't hurt anything either, although it might start sucking back depending on what temp it fermented at.

 

[MaxStout]

Will need to think any that one.
Anyway, anticipating a cold crash, the temp was down to 54F. Hope I didn't spoil it. I'm having it increase back to where it was at 66F.

Would look something like this (not my pic).

 

[Art2019]

Would look something like this (not my pic).

View attachment 858801

Think my id is about 2". Wouldn't that still suck O2?

 

[Art2019]

That shouldn't hurt anything either, although it might start sucking back depending on what temp it fermented at.

It started fermenting at around 66F-67F.

 

[MaxStout]

Think my id is about 2". Wouldn't that still suck O2?

Not if it's a closed system. Airtight fit with one end in the carboy mouth, the other end submerged. No entry point for air.

BTW, 2" seems large. You want tubing that friction fits on the INSIDE of the neck.

 

[mac_1103]

It started fermenting at around 66F-67F.

So I guess it depends on the ID of that blow off tube and how much head space you have in your carboy. Have you noticed it starting to pull liquid back into the tubing?

 

[Art2019]

Not if it's a closed system. Airtight fit with one end in the carboy mouth, the other end submerged. No entry point for air.

BTW, 2" seems large. You want tubing that friction fits on the INSIDE of the neck.

It's as closed as it can get with a stopper & airlock. The will be air that was already inside tube. After I remove that, it's open so I guess what's the point of having a closed transfer after cold crash?

I'll need to measure once stopper's out. ID looks wider than 1", could be wrong. Carboys are standard, for the most part.
What fermenter do you have? I have been using a FastFerment conical over last few years but never had temp control so to do that, I needed to repurpose my chest freezer to a cold chamber, which isn't very cold now since I'm chilling at a higher temp. That's where I had my kegged brew.

 

[Art2019]

So I guess it depends on the ID of that blow off tube and how much head space you have in your carboy. Have you noticed it starting to pull liquid back into the tubing?

Not at all.

 

[MaxStout]

It's as closed as it can get with a stopper & airlock. The will be air that was already inside tube. After I remove that, it's open so I guess what's the point of having a closed transfer after cold crash?

I'll need to measure once stopper's out. ID looks wider than 1", could be wrong. Carboys are standard, for the most part.
What fermenter do you have? I have been using a FastFerment conical over last few years but never had temp control so to do that, I needed to repurpose my chest freezer to a cold chamber, which isn't very cold now since I'm chilling at a higher temp. That's where I had my kegged brew.

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.