Balancing pressure in fermentation vessel.

[Top Cat]

Guys, advice please!
I’ve recently changed from a plastic to a more up market stainless fermentation bin.
As the top has a tri clamp hole I decided to do away with a standard bubbler and use a cornie gas disco fitting, connected to a bit of 3/8 gas pipe submerged in a small container of starsan.
Worked well during fermentation, but as I reduced the temperature down to about 1c for cooling, I got the collapsing can affect as we learnt in physics at school.
Basically the fermentation vessel lid is a very good seal, and during the cooling stage pressure reduced inside sucking the starsan into the brew, and I hope I haven’t ruined it!
I assume the pressure will regulate itself when I bring the temperature back up to about 12c for conditioning.
In the meantime I’ve replaced the cornie disco with a 90 degree barb and 2.5psi relief valve fitting, and put some CO2 back into the vessel.
Due to an arrangement of toggle clamps on the bin, in a restricted area in my fridge, I can’t remove the clamps whilst in situ.
How do you get round balancing the pressure better than I have?
Thanks all in anticipation.

[f00b4r]

The Starsan is unlikely to have ruined it. It might help to let us know what the actual fermenter is as they are not all built equally, especially with regard to pressurising them (it might change the advice somewhat).

[Top Cat]

The Starsan is unlikely to have ruined it. It might help to let us know what the actual fermenter is as they are not all built equally, especially with regard to pressurising them (it might change the advice somewhat).

The fermentation vessel is a BrewBuilder standard 33 litre flat bottom bin with a 1.5” tri clamp hole in the lid and bottom outlet. The lid is attached with six toggle clamps.

[Jocky]

I have the mini fermenter from BB and that certainly doesn't take much pressure. The silicone seal leaks even under a couple of psi.

To avoid the suck back problem I attach a mylar foil balloon with CO2 in it in place of the airlock before cold crashing. If you don't have a CO2 bottle to fill the balloon then you can collect the CO2 towards the end of fermentation.

[Top Cat]

I have the mini fermenter from BB and that certainly doesn't take much pressure. The silicone seal leaks even under a couple of psi.

To avoid the suck back problem I attach a mylar foil balloon with CO2 in it in place of the airlock before cold crashing. If you don't have a CO2 bottle to fill the balloon then you can collect the CO2 towards the end of fermentation.

Jockey, excuse my ignorance, I see how a balloon will work. I have no problem with CO2 and any fittings necessary, where do I get a Mylar balloon from?

[Jocky]

I have the mini fermenter from BB and that certainly doesn't take much pressure. The silicone seal leaks even under a couple of psi.

To avoid the suck back problem I attach a mylar foil balloon with CO2 in it in place of the airlock before cold crashing. If you don't have a CO2 bottle to fill the balloon then you can collect the CO2 towards the end of fermentation.

Jockey, excuse my ignorance, I see how a balloon will work. I have no problem with CO2 and any fittings necessary, where do I get a Mylar balloon from?

Childrens parties, theme parks, funfairs.


(Or Amazon: https://www.amazon.co.uk/Balloons-Spher ... B07VHBVT4X)

[Top Cat]

Ha ha! Have done a bit of research on the balloon. Thought it might be a bit of refined kit, but turns out to be a party item! A bit primitive, but if you find it successful, it’s a cheap option. How do you attach it Jocky?

[Jocky]

I cut the filling end off the balloon, stuck a piece of silicone hose in and taped/sealed it with duct tape.

The lid of the fermenter has a 90 degree barb on it for a blow off/airlock. The silicone hose slips over that.

The fermenter originally came with a barb that was something like 8mm, but I've since replaced it with a bigger one so I could use 1/2" tubing for the blow off and balloon.

[guypettigrew]

Try 'cold crashing' ( I hate that term) in two stages. Drop the beer to 12°C once the primary fermentation has finished. This won't suck anything back up through the blow off tube.

After a few hours you'll see bubbles very, very slowly coming through the blow off tube. Then drop the temperature to 4°C or whatever. No suck back.

Guy

[Top Cat]

Try 'cold crashing' ( I hate that term) in two stages. Drop the beer to 12°C once the primary fermentation has finished. This won't suck anything back up through the blow off tube.

After a few hours you'll see bubbles very, very slowly coming through the blow off tube. Then drop the temperature to 4°C or whatever. No suck back.

Guy

That sounds simple enough Guy, and worth a try.
I noticed the majority of the starsan was sucked back during the temperature dropping from 7to1c, do you know how your method works?

[guypettigrew]

The blow off tube and the inside of the FV re-pressurise when the beer is dropped to 12°C because the beer continues to ferment very slowly.

The drop to 4°C isn't enough to reduce the pressure far enough to pull any liquid back through the tube into the FV. My blow off tube is about a metre long, which is the distance from the top of the FV to the bottom of the bucket it sits in.

I've never gone as low as 1°C, never had the need. 4°C drops enough yeast out when left for 24 hours or so.

Guy

[Top Cat]

The blow off tube and the inside of the FV re-pressurise when the beer is dropped to 12°C because the beer continues to ferment very slowly.

The drop to 4°C isn't enough to reduce the pressure far enough to pull any liquid back through the tube into the FV. My blow off tube is about a metre long, which is the distance from the top of the FV to the bottom of the bucket it sits in.

I've never gone as low as 1°C, never had the need. 4°C drops enough yeast out when left for 24 hours or so.

Guy

Understood.
Think I’ve a few issues I can solve.
The first one is my makeshift blow off. As it consists of a cornie gas in post, an elbow, and about 4 inches of 3/8 pipe, resting in a small container on the lid, it doesn’t take much force to bring the starsan back into the brew.
Issue 2. I might be reducing the clearing temperature too quickly, and it may help to stop at around 4c, as I’ve done this before.

[guypettigrew]

You've got it sorted!

Longer blow off tube, slower cooling. Job done!

Guy