Using corny keg to catch CO2 to then prevent O2 ingress when chilling

[timtoos]

Just an idea,

What's peoples thoughts on venting the fermenter blow-off through a corny keg? When I cold crash I could then connect a balloon to keg or gas the keg up and use a regulator to drip feed co2 if the fermenter requires gas upon cooling.

I have attached a doodle of what I mean.

The fermenter is a SS Brewtech chronical, it cant be used under massive pressure but it does have a PRV so any excess pressure would be vented off.

Thoughts?

PS I would not attach the keg when the fermentation is going crazy so that nothing is blown into the keg and the keg would be sanitised before any use.

 

[DocAnna]

Hi there's been a few goes at this, and I routinely now use one of these attached at cold crash and if moving a fermenter to stop it sucking in air while carried. How to: Balloon CO2 collection (Bruloonlock)
But there's lots of merit in using a keg since it can purge it for you during fermentation:
https://www.thehomebrewforum.co.uk/...ls-cornys-how-do-you-do-it.95761/post-1067780
Personally I use the balloons since they work with plastic bucket fermenters as well as the pressurised versions.

 

[JockyBrewer]

You won't need the balloon if you just have a larger sanitiser container and flip around the keg connections (so the fermenter is on the gas side). The keg will suck sanitiser back into it, but only as much as gas in the headspace of your fermenter shrinks.

Like Anna I attach a balloon to my fermenter when cold crashing. I just partially fill it with some CO2 from my CO2 tank rather than capture from fermentation.

 

[timtoos]

Thanks all.
I was thinking of swapping the posts on the keg when it comes to cooling but leave like this whilst CO2 is produced

 

[JockyBrewer]

Thanks all.
I was thinking of swapping the posts on the keg when it comes to cooling but leave like this whilst CO2 is produced

Another thing you could do is fill the keg with sanitiser, then let fermentation push it out into a big jug.

To do that you need the fermenter on the gas side though.

 

[timtoos]

The reason I attached to the liquid out post was so that it could fully purge the O2 out of the keg (or I think it would)

 

[timtoos]

Another thing you could do is fill the keg with sanitiser, then let fermentation push it out into a big jug.

To do that you need the fermenter on the gas side though.

I didnt want to fill the keg with anything, I feel that the back pressure against the fermenter would not be great. Is this incorrect?

 

[Agentgonzo]

I didnt want to fill the keg with anything, I feel that the back pressure against the fermenter would not be great. Is this incorrect?

Back pressure doesn't cause a problem at the homebrew scale (it can for commercial breweries where their fermenters are 5/10m tall).

If back pressure was a problem, then bottle conditioning (carbonation) wouldn't work.

 

[timtoos]

Thanks all

 

[StJayJay]

I’d not noticed the issue with my plastic buckets because of the seals weren’t great so wasn’t really drawing in any sanitiser on chilling. When I upgraded, first brew i cold crashed sucked up about 500mls of sanitised water. Rather than try anything too complicated, I’ve put a John guest shut off valve on the blow-off tube and it’s done the trick providing you remember to shut it off.

 

[JockyBrewer]

I’d not noticed the issue with my plastic buckets because of the seals weren’t great so wasn’t really drawing in any sanitiser on chilling. When I upgraded, first brew i cold crashed sucked up about 500mls of sanitised water. Rather than try anything too complicated, I’ve put a John guest shut off valve on the blow-off tube and it’s done the trick providing you remember to shut it off.

That pressure differential is going to go somewhere unless you're using a fermenter that can hold negative pressure.

 

[Buffers brewery]

I tried displacing water from a container using gas from the fermentation bucket. Didn’t work. Gas dissolved into the water quicker than it could push it out!
Use balloons now filling three during fermentation and after high krausen. I use one balloon during cold crash and the gas from the other two to fill a King Keg pressure barrel prior to closed transferring.

 

[Braufather]

Another thing you could do is fill the keg with sanitiser, then let fermentation push it out into a big jug.

Or another empty keg ready for the next one. i think I’m going to try this.

edit. just read @Buffers brewery post above so maybe not.