Will a krausen form with no constant pressure relief?

[badbrew]

I was thinking of getting something like this:

...and using it to pressure ferment. I figured I'd set my regulator to 5 psi, plug this device in and adjust it down to just start opening and then ferment at <5psi. However, I was concerned about the blow off. So I am wondering if the krausen could even form with no constant relief for the co2 build up. Any ideas?

 

[TopherM]

What is that thing? Plenty of people and commercial breweries ferment under pressure, so it will work, but what is that thing?

 

[StMarcos]

I'm not quite sure what you're asking. Standard ferms in a bucket or whatever have constant pressure relief. Folks spunding and fermenting at 15psi also have constant pressure relief. So.... what do you mean by NO constant pressure relief? Krausen is lessened when fermenting under pressure above the ambient, if that's what you mean.

 

[badbrew]

Yeah I guess it would be opening and closing all the time. Didn't think about that. It is a device morebeer sells for transferring between kegs while filtering to purge the gas in the incoming keg. I'm just concerned about blow off if I got it for fermenting.

 

[StMarcos]

I'd either use plenty of headspace, antifoam, or a separate 'overflow' container, and put the prv on that.

 

[badbrew]

I'd either use plenty of headspace, antifoam, or a separate 'overflow' container, and put the prv on that.

I guess I could use the fermcap, but I'd hate to rely on it exclusively for this. I am not looking to brew less than 5 gallons so the head space is what it is. As for the overflow, I was planning to take the diptube out and hook up a hose to the out connector and stick it in a cup of liquid if I had too. That is what I was hoping to avoid though. I wonder if there is a magic pressure that will keep the krausen in check. 5? 10? 15? 20? I was also curious how much pressure would build up in 12 hours if I wanted to experiment with bleeding the CO2 a few times each day. Maybe a little risky.