Co2 transfer loop

[Paulus]

I'm pretty sure you just need :-
1. Purge the keg and fill it to the same pressure as the fermenter or less.
2.The bottom of the fermenter must be higher than the top of the keg
3.Connect the fermenter liquid post to the liquid post on your keg
3.Connect the gas post of the keg to the gas post of the fermenter.

 

[MashBag]

This seems a bit more complex than the one I had envisaged? The spunding valve is fully open, but the pressure into the destination keg is reduced by the inline regulator which shows the pressure on the output side. The open spunding valve's manometer shows the pressure on the input side.
View attachment 105580

I have been working on this and I think you might have the best idea.

If the knobs on these units both control pressure accurately, is the only difference that one vents the co2 to atmosphere and the other has a hose fitting and the gauge range?

And why are there sooo many replacement gauges for sale?

 

[Caramel Ox]

I have been working on this and I think you might have the best idea.

If the knobs on these units both control pressure accurately, is the only difference that one vents the co2 to atmosphere and the other has a hose fitting and the gauge range?

And why are there sooo many replacement gauges for sale?

You can swap out the gauge for a different range. There is an eBay supplier that lets you choose up front rather than buy and replace.

 

[MashBag]

Righto
That explains the gauges. Cheers

 

[Davegase]

I'm pretty sure you just need :-
1. Purge the keg and fill it to the same pressure as the fermenter or less.
2.The bottom of the fermenter must be higher than the top of the keg
3.Connect the fermenter liquid post to the liquid post on your keg
3.Connect the gas post of the keg to the gas post of the fermenter.

I've been using that method for about four years.
Actually commented on that YouTube video about three months ago.
After purging the keg I pressurize it to slightly above the fermenter pressure.
Then I connect the two gas posts first which equalizes the pressure. Then connect the two liquid posts, then a quick left on the prv of the keg to start the flow, gravity does the rest.

 

[Davegase]

I have been working on this and I think you might have the best idea.

If the knobs on these units both control pressure accurately, is the only difference that one vents the co2 to atmosphere and the other has a hose fitting and the gauge range?

And why are there sooo many replacement gauges for sale?

The main difference between the two is the direction the gas travels.
On one the gas passes through the gauge before the diaphragm and on the other it passes through the diaphragm before the gauge.
So the red one is a spunding valve and the white one is your secondary regulator.

 

[Buffers brewery]

@MashBag this is a very interesting but for me confusing thread so can I ask a couple of questions? I understand this process is to produce a pressurised gas supply to dispense beer from another keg, so how is the gas produced? Is it from a pressure fermenter or a dedicated corny with a sugar/yeast mixture? If the latter how is this purged? When the gas supply runs down do you re-dose the mixture with more sugar? If so how to keep air out and at what point does the mixture need to be changed? Cheers

 

[MashBag]

The principle is rolling gas. The next beer up provides gas for one that's tapped.

The first test (wip) is a 40 pint standard batch into two cornies.
Leaving obvs a large headspace.
Dropped warm 4 days about 90% done. Both cornies primed with 100g sugar.

These are both currently at about 2 bar. They will provide the gas for the current corny on dispense.

Next and obvs one. Using an empty tank as a buffer to store.
Thinking: you are overpressuring your beer when you prime with 100g. Why blow it off (spund) why not transfer to another tank.

Third test will be corny as gas tank (basic sugar wash fermented in the corny) to produce co2. That's the easy one.

Purging is not a big deal. Once the system is running. Yeast does use air up.

Pressure fermentation yes into. All cornies, after the first stage.

 

[Buffers brewery]

OK. Thanks for that end to end explanation.
When I was reading through it yesterday it occurred to me that if you were able to prime more accurately you could avoid producing excess gas that needed to be stored or vented. Then if you had a way of “injecting” an additional dose of sugar solution you could produce some more gas to continue dispensing. This was a process used by a past member, @terrym, but he used pressure barrels and just opened the lid to add the sugar.
I can visualise a complicated gizmo that would connect to the gas post and consist of a (medical) 3-way tap with the gas quick connect one branch, a small syringe on another branch and a tube on the third branch going to a container of sugar solution. Process would involve sucking solution into syringe switching the tap then squirt solution into keg. Repeat until sufficient sugar has been added to generate the required pressure. I guess the issue with approaching is you have to wait for the yeast to munch through the sugar and create the gas
Watching progress with interest

 

[MashBag]

Had a not quite, but similar thought. Priced up the bits and a used corny was cheaper. So I could just open it and lob another one on. Which then lead onto the daisy chain thought.

Tbh it is a bit odd, it does require a bit of stock control, but I am quietly confident at the moment.

The only issue is a the keg land reg. I really fancied one link does everything. I think I am going to need another - straight through - for dumping.

 

[MashBag]

Is it a simple gas control board. One gauge, and two simple valves either side?

 

[RoomWithABrew]

That then begs another question, why dont we capture the Co2 off of a pressure ferment to push starsan through a daisychain?

I have done for ages and pressure the kegs up to the spunding pressure of the fermenter.
Don't force starsan through your spunding valve.

So you capture the CO2 in the kegs post purge of starsan.
After cold crash of the beer being fermented you'll find that the pressure in the keg is greater than in the fermenter and you use this pressure to kickstart and offset the volume changes.

 

[Davegase]

I am now wondering if I should start using the Co2 corny to push starsan out of a couple of daisychained kegs with the spundy at the end of the daisychain.. to have clean, oxygen free cornys ready to fill .

I've done that quite a few times,
After the keg at the end of the daisy chain I have a 2 litre pet bottle with the kegland fitting that has two ball lock posts. The spunding valve is fitted to that for insurance against overflow from the last keg.

 

[RoomWithABrew]

Just purge the kegs into an open collecting vessel for the starsan. Watch out that you don't set up a siphon or just watch carefully if you are siphon purging.
The tube into the open collecting vessel is submerged in the starsan so is airlocked.
Then when they are purged put the spunding valve on.

Don't start the starsan purge until your brew has used up all of the headspace air.

Remember as well that you can use the residual gas in a corny post use to purge or start a purge on another keg.