How to Cold Crash in Fermonster with Airtight Lid?

[IrondaleBrewing]

In order to start doing simple closed transfers with a 3-gallon Fermonster with a spigot I just added a ball lock gas post to one of the sealed Fermonster lids. I'll use a quick disconnect and a blowoff tube during fermentation and I'm clear on how to do the transfer to the keg.

What I'm wondering now is how to handle cold crashing.

I'm assuming that if I just remove the blowoff tube, leaving the fermenter airtight, the drop in temperature and internal pressure will suck the walls of the fermenter in and potentially damage the fermenter. And of course leaving the blowoff tube on doesn't seem to solve the problem of air and sanitizer getting sucked in.

My first thought was to remove the blowoff tube and apply 1-2 PSI of CO2 during cold crash (according to the company that makes the Fermonster it's OK up to 5 PSI), but I'd love to hear techniques people have used or general ideas on this.

Thanks!

 

[Broken Crow]

maybe fill a mylar ballon with CO2, attach it to a gas disconnect and plug it in?

 

[fluketamer]

co2 trap

you can make this at home very easy.

you could prolly do this with carb caps tee pieces and pet bottles also so you wouldnt have to drill holes in mason jar lids.


looking at this pic i dont think the airlock is actuaslly necessary cause the jar on the left acts as a blow off so no need for the airlock i dont think

 

[IrondaleBrewing]

co2 trap

View attachment 842112

you can make this at home very easy.

you could prolly do this with carb caps tee pieces and pet bottles also so you wouldnt have to drill holes in mason jar lids.


looking at this pic i dont think the airlock is actuaslly necessary cause the jar on the left acts ass a blow off so no need for the airlock i dont think

Thanks for the suggestion! That looks slick.

 

[IrondaleBrewing]

maybe fill a mylar ballon with CO2, attach it to a gas disconnect and plug it in?

Thanks! I've considered the mylar balloon approach but from what I've read and watched getting the timing on that right is pretty tricky. Maybe that concern is overinflated (ha!). Or is that more of a concern if you're using a traditional airlock and stopped to begin with and have to swap it out at the right time?

 

[tdf]

Thanks! I've considered the mylar balloon approach but from what I've read and watched getting the timing on that right is pretty tricky. Maybe that concern is overinflated (ha!). Or is that more of a concern if you're using a traditional airlock and stopped to begin with and have to swap it out at the right time?

If you have one, you can just fill the balloon with a co2 tank instead of trying to time the swap to fill it with fermentation co2. Then you can just wait till fermentation is done, fill the balloon, swap it, and then crash.

 

[day_trippr]

My first thought was to remove the blowoff tube and apply 1-2 PSI of CO2 during cold crash

Or just 0.4psi. That's what I do, connecting a cheap BBQ gas grill regulator down stream from a primary CO2 regulator to provide a reliable low pressure source to apply to the fermentor head space...

Cheers!

 

[mac_1103]

I've considered the mylar balloon approach but from what I've read and watched getting the timing on that right is pretty tricky.

Using a tee and a check valve takes all the guesswork out of it. Like this. Also DIY-able if you're a real cheapskate.

 

[IrondaleBrewing]

Thanks so much to everyone for all the great info and suggestions! I learn a ton with every question I ask.

 

[Bobby_M]

You can hook your co2 up to it set to less than 1PSI and it will keep it topped off. You can use my product the cold crash guardian that fills a bladder with CO2 naturally and vents the rest. You COULD also use like 25 feet of tubing for your blowoff. I would suck a lot of starsan back into it, but won't make it all the way... probably.

 

[IrondaleBrewing]

You can hook your co2 up to it set to less than 1PSI and it will keep it topped off. You can use my product the cold crash guardian that fills a bladder with CO2 naturally and vents the rest. You COULD also use like 25 feet of tubing for your blowoff. I would suck a lot of starsan back into it, but won't make it all the way... probably.

Thanks! Looks like the Cold Crash Guardian is out of stock but I'll keep my eye out.

 

[MikeCo]

Or just 0.4psi. That's what I do, connecting a cheap BBQ gas grill regulator down stream from a primary CO2 regulator to provide a reliable low pressure source to apply to the fermentor head space...

Cheers!

Do you have a gauge on the gas grill regulator to set it to 0.5 psi?

 

[day_trippr]

Like all cheap BBQ regulators, this one is fixed to 11" WC which is roughly 0.4 psi. I connect it to a primary CO2 reg (arbitrarily set to ~20 psi) when needed...

That dual CO2 reg shown serves two fridges side-by-side so there's a 2nd BBQ reg for the other fridge as well as I commonly have two batches fermenting at the same time...

Cheers!

 

[Cameronl]

Thanks! Looks like the Cold Crash Guardian is out of stock but I'll keep my eye out.

Plus one on the Cold Crash Guardian. Works great.

 

[Brewer Mike]

I've just crashed in the Fermonster (7.9 g). It did suck the sides in, but they pop back out with a little pressure, or return to original temp with no ill effects.

 

[IrondaleBrewing]

I've just crashed in the Fermonster (7.9 g). It did suck the sides in, but they pop back out with a little pressure, or return to original temp with no ill effects.

Great to know! Since my next batch will be the first time I'm using this method I'm probably overthinking it.

 

[Bobby_M]

I've just crashed in the Fermonster (7.9 g). It did suck the sides in, but they pop back out with a little pressure, or return to original temp with no ill effects.

As long as it's not too extreme it should be fine but after a few cycles, those spots that creased will definitely cause cracking and prematurely wear the tank out. It will crease at the same spots each time.