Cold Crash “cask breather”

That's my understanding. I've read about these before, I'm not quite sure how this is better than just using a normal (primary) regulator directly to the keg. Maybe the idea is that it's a very accurate/precise fixed 0.4 PSI (or 1 PSI...I've heard that spec also) and that typical regulator gauges aren't very accurate in that range? I don't really know why that would matter though. I don't crash all my batches in the fermenter, but when I do, I don't have any problems maintaining a small pressure with my regulators.

ETA: I forgot to mention that what these breathers are really designed for is to replace cask headspace with CO2 as beer is being dispensed. But I have seen posts from folks using them for cold crash purposes.

 

A low pressure propane regulator gives a pressure of 10 inches of water. I have one to use with the hand pump, it will push the beer up from the corny, but not to the hand pump.

 

I attached a barb on a Mylar balloon about 4 years ago and use that plugged into my bubbler tube while crashing. I just charge the balloon half full with CO2. I’m pretty good at estimating how much shrinkage the beer will have. I also use it when I’m kegging so it sucks in CO2 and not just air from the room. Hardest part was attaching/securing the barb into the balloon. I’ve only changed the balloon once when I decided to try to let the balloon fill up with co2 from the end of fermentation. The smell of the co2 was pretty funky with all the other aromas included.