Pressurised fermentation gas anyone?

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Buffers brewery

Complicated Brewer
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Yes, it's another one of those mad Buffers Brewery brainwaves.

I've posted on other threads my ideas about balloons, barrels and fermentation gas. Well I've just had the opportunity to try out my latest idea.

Having just had a brew day, I had a supply of fermentation gas coming from my brew fridge and after I had collected a couple of balloons worth for my keg flushing I was able to test my prototype BIAB = Balloon in a barrel.

I modified a 5 gallon pressure barrel and cap so that I could fit a Mylar balloon to the cap that I could connect to my fermentation gas supply. The barrel wall was modified so that the barrel interior could be pressurised independently of the balloon. Cue first slide....
IMG_20221023_140142955.jpg

This pic shows a deflated balloon connected to the "Air IN" corny post that's connected to the barrel interior. The red hose is connected to the brew fridge (on the left) and is connected to the barrel cap that supplies the (fully deflated) balloon inside the barrel.
After about an hour the external balloon is inflated...cue second slide
IMG_20221023_152419395.jpg

The external balloon has been inflated by the air in the barrel that has been displaced by the internal balloon inflating with fermentation gas.
Now the test. Checking the pressure gauges both were reading zero. Cue slide 3.
IMG_20221023_152432966.jpg

Disconnecting the external balloon and the internal balloon connections I attached a spray pump to the Air IN connector and pressurised the barrel, increasing the pressures in both barrel and balloon (remember they are independent of each other). Cue slide 4
IMG_20221023_154702324.jpg

Left it for half an hour to see if there were any leaks!
IMG_20221023_165220879.jpg

Bu66er! Very slow leak at the barrel connection where I'd try to seal it with silicone sealant (unsuccessfully aheadbutt)
Decided to ignore it as it did not impact the integrity of the fermentation gas circuit. Pressurised it up to 10 p.s.i. Cue slide 6
IMG_20221023_165428990.jpg

That is the pressure of the fermentation gas that could be used to top up a pressure barrel or corny for beer dispensing (not carbonating).
I have a barrel in my barrelator that will need a gas top up after another couple of pints. Watch this space for an update!
 
Was this a test from a CO2 cylinder, or from another source? Would this come from the active fermentation in the real setup?
I pumped the barrel pressure up using air from the spray pump. As the barrel pressure increases it squeezes the internal balloon increasing the fermentation gas pressure. The gas in the internal balloon is fermentation gas collected today from the FV in my brew fridge after yesterday's brew day. Once the internal balloon is full it's disconnected from the FV and that's it. I reckon if you set your dispensing pressure to 7 p.s.i. there should be enough gas for 2-3 gallons of beer. The barrel internal pressure would need to be pumped up with the spray pump as the fermentation gas is used until it's all gone, zero internal balloon pressure and 5-10 p.s.i. barrel pressure.
 
Is the external mylar balloon used to check that the internal barrel balloon is filling and you know when max fill is being reached, as a safety check?
 
I admire your ingenuity, but it seems a lot of work and effort to save a small amount of cylinder gas!
Thanks and you may be right :laugh8:. A lot of the things I do are just for the amusement factor and also to see if a crazy idea actually works! The BIAB (balloon in a barrel) approach is not particularly practical as I estimate you would need 2 BIAB set-ups for every 5 gallon keg. If you have more than one keg on the go at a time then 2 BIABs for each keg, so not too practical. However, a couple of BIABs made from discarded pressure barrels could provide an emergency back-up when a cylinder runs out and can’t be replaced for a week or two.
 
Brewers here in NZ have said that CO2 prices have rocketed and availability plummeted. Only one place in NZ makes CO2 to go in bottles now so very much a closed market.
I'm using ferment CO2 for purging and spunding my beers so only serving gas from the keg fridge needed.
 
This is great. Brilliant work. I love making the most of fermentation gas. I flush all my Cornys with fermentation gas then do a closed transfer when it's finished fermenting. I keep it under pressure too so that I can jump start the syphon without having to hookup the big gas canister. It's all very satisfying!
 
It’s not just fermentation gas that can be re-cycled. Recently I realised when my pressure barrel (could be your corny) is empty (of beer) there’s still pressurised CO2 in it so I connect one of my empty balloons and de-pressurise the barrel (could be a corny) in to it and collect the surplus gas.
 
It’s not just fermentation gas that can be re-cycled. Recently I realised when my pressure barrel (could be your corny) is empty (of beer) there’s still pressurised CO2 in it so I connect one of my empty balloons and de-pressurise the barrel (could be a corny) in to it and collect the surplus gas.
That has given me an idea (no doubt what some already do). I'm going to use the pressurised blown keg to pressure transfer from keg 2 with sanitizer to keg 3 that's empty. That'll give me keg 2 partly gassed and ready for a closed loop transfer (hopefully).
 
That has given me an idea (no doubt what some already do). I'm going to use the pressurised blown keg to pressure transfer from keg 2 with sanitizer to keg 3 that's empty. That'll give me keg 2 partly gassed and ready for a closed loop transfer (hopefully).
yep been doing this for a while, often not enough gas pressure to complete the job but gets it well on the way.
 
yep been doing this for a while, often not enough gas pressure to complete the job but gets it well on the way.

Did it today. 2 blown kegs was easily enough to empty and pressurise 19L keg full of sanitiser and then close loop transfer. I also used the excess to purge a 5L keg and close loop transfer the remaining 3L of beer into that keg. Good job it worked as my gas reg is showing almost empty.
 

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