Cold crash suck back options

Here's a link to a thread that discussed this from 16 months ago that might be of interest to you.
https://www.beeradvocate.com/commun...n-due-to-suck-back-when-cold-crashing.445260/

 

Did you fill the balloon with CO2?

Cheers!

 

I usually just swap the airlock for one with vodka or starsan in it.

 

That would still permit air (oxygen) getting into the carboy due to 'suck back'. I believe the OP is concerned about the resulting oxidation off-flavors.

Cheers!

 

Use a Mylar balloon that won’t require pressure to inflate. Install it on the airlock when you still have a few gravity points to go then let the completing fermentation inflate it. When you cold crash, the balloon will deflate without exposing your beer to anything other than the CO2 it produces.
I can’t take credit for this idea but it will work.

 

My experience hasn't seen enough "suck back" to dry out an airlock. Certainly seen enough to pull a little of the water back into the beer, but not enough to create the issue in question

 

The issue is not drying out the airlock. When 'suck back' occurs air (oxygen) is pulled through the airlock and into the carboy. Basically the opposite flow from fermentation:

• Fermentation: CO2 out-gasses out of the airlock.
• 'Suck back': Air (oxygen) in-gasses through the airlock into the carboy

Oxygen (oxidation) is one of the big 'enemies' of beer.

Cheers!

 

Ah ha, I use the cheap S type airlocks when past any blowoff risk. They will not bubble backwards until virtualy dry.

 

These will allow air/oxygen into your fermenter once there is negative pressure. They will probably not let the airlock liquid in. 3 piece airlocks, on the other hand, will pull the airlock liquid into your beer, but will not expose it to air unless the liquid level gets low enough.

I don't want airlock liquid or air in my fermenter, personally. My solution so far has been to not cold crash most of the time. I was thinking of starting to cold crash under pressure in a secondary keg the doing a closed transfer to serving keg. Now I may try this balloon idea.

Seems to me that inflating the balloon with CO2 from fermentation before cold crashing would be ideal.

 

If you come up with the solution here please don't keep it to yourself.

Cheers!

 

Take the airlock out, cover the airlock hole with foil, cold crash for a few days, then keg. Done.

 

How does that stop air (oxygen) ingress during the cold crash process?

Cheers!

 

It's true that the inside of the fermenter won't be exposed to the atmosphere directly (via the airlock path). But liquid in the airlock will not completely prevent O2 from entering the fermenter through there, even if the liquid level is full. And "negative" pressure will make it easier for O2 to enter.

For my money (and labor), the best "airlock" is a spunding valve.

 

I do something like what the OP is mentioning. That idea with Mylar is better. I believe the ziplock bags are more O2 permeable- that's why there is a second class of "freezer bags"; a regular ziplock will allow too much O2 through for the long term storage assumed with frozen foods. However the idea of filling with CO2 from off-gassing beer is important, if the pressure within is greater than the pressure outside, you can avoid gas permeating any membrane. Even a beer that has finished fermenting and reached a static gravity will still off gas until the quantity of gas in solution reaches equilibrium with it's atmosphere (1 vol.). It only takes a couple hours to adequately fill the bag/vessel in most of my experiences.

 

I went to the dollar store and purchased a package of 3-punching balloons for $1. I take one of the balloons and fill it up quite a bit with c02 and tape a blow off tube on it. Then I stick the blow off tube in the fermenter. It keeps the fermenter from sucking and only c02 fills the headspace

 

Here is what I do

 

It will match her stainless steel kitchen appliances?