CO2 Purging (Sours and NEIPA's and the like)

[Nuke Hunt]

Hey brewing legends.

I am just venturing into the world of sours and Neipa's - and a lot of reading points to purging the kettle/fermenter (dry hopping in primary fermentation for NEIPA's).

I don't have a keg system or CO2 tanks, not that fancy yet - only a 30L stock standard plastic fermenter and bottling.

I do have a soda stream system though, so I think if I attach some tubing to that outlet I can use that to purge the kettle for souring (and cover with gladwrap) - or purging the fermenter during primary to dry hop a Neipa (gonna have a go this weekend).

So my questions are:

A - do you think the old MacGuyver soda stream thing will work?
B - how much do you put in - eg in a 30L fermenter with a batch of, lets say 20L?

I know NEIPA's are best in a keg a not a bottle but FK it, gonna do it anyway.

Is there a better set up to use.

Thanks for any suggestions.

 

[neal32]

Is there a better set up to use?

Well, arguably. I use a kegmenter and I ferment the last half to 25% under pressure. Then crash chill once done. Then fill via a filter into an already purged keg with keg hops under counter pressure.

That's how I eliminate the oxygenation issue. My beers never touch oxygen until they're coming out the keg tap. Also your plastic fermenter will let oxygen in at all times.

As to whether it's of critical importance, I couldn't tell you.

To answer your questions;
A. No
B. Depends on batch size, but everything that's not beer will be air. But it's unimportant as the oxygen will be used pre-ferment if you have a good seal. The plastic fermenter is permeable to air though (I think).

 

[sp0rk]

If you're using L Plantarum (either Ethical Nutrient IBS capsules or Lallemand Wild Brew) for kettle souring, you don't need to purge with CO2
Milk The Funk podcast did an episode with Omega labs and they said it's not needed
You can pre sour with lactic acid to 4.5pH if you're really worried, but I don't and it's never caused any issues for me
I do wrap with gladwrap, but don't flush with CO2
From what I understand, if you're using a pure lacto strain then CO2 isn't really that important, it's more when you're culturing it from grains and there is possibly other bacteria that you want to suppress so the lacto can dominate

 

[donald_trub]

With kettle souring I thought the same bugs responsible for culturing from grain are still present when you've got your mash runnings sitting in a kettle for a day or so. I've also done the glad wrap covering with IBS pills, but understood I was still taking a little risk in something else taking off and ruining the batch. Not sure how a particular brand of lacto would prevent that?

 

[sp0rk]

With kettle souring I thought the same bugs responsible for culturing from grain are still present when you've got your mash runnings sitting in a kettle for a day or so. I've also done the glad wrap covering with IBS pills, but understood I was still taking a little risk in something else taking off and ruining the batch. Not sure how a particular brand of lacto would prevent that?

L Plantarum is known to work quickly and it's very oxygen tolerant
Usually if you're inoculating with a pure strain, you boil for say 15 minutes, chill to 35c then pitch your lacto strain
So you've killed anything that was on the grain
If you're using a culture that you've used raw grain for, generally the lacto has grown and taken over anything else that's in there, so you're pitching a good healthy cell count of lacto that will go to town in your boiled mash

 

[MHB]

Once Lacto gets going the pH plummets, most bugs cant handle low pH's or at least everyone using acid sanatisers hopes that's the case....
Many microorganisms modify their environment to make life hard for competitors, making alcohol, removing oxygen, adjusting pH, making antibiotics... If there's a way to get an advantage somewhere evolution has been test-driving it.
Mark