Carbonating kegs from fermentation gases

[pirateagenda]

Have 2 40L batches fermenting quite vigourously at the moment, one under pressure and the other into a bottle of star san air lock. Both have beautiful aromas and have been expelling quite a bit of gas, which had me thinking.

Has anyone had any success in carbonating kegs, using gas from the ferment? I'm not talking about capping the ferment to let the beer naturally carbonate, rather daisy chaining some corny kegs of flat beer to the gas out on a pressure fermenter and letting the ferment gasses carb up the other kegs. Pressure could be controlled via a spunding valve on the last keg in the chain.

I can think of 2 benefits to this if it worked:
1. Save on bottle gas
2. Utilise the hop aromas lost during ferment to maintain/improve aroma in the other beers (obviously would need to be of similar style).

 

[mtb]

That's a really interesting idea.. I guess it really depends on just how much the "shared" headspace/aroma would affect the ongoing aroma of each beer. Would they all meld into one or retain some individuality?

 

[Mall]

http://aussiehomebrewer.com/topic/90341-spunding-valve/?hl=+pressure%20+ferment

 

[mtb]

It would pay to read the OP Mall. Pirate specifically stated that this wasn't relating to pressure fermentation.

 

[klangers]

I've been toying with the idea of compressing and storing ferment CO2 in kegs, at 6 bar or so. While liquifaction and high pressure storage is out of the realm of a homebrewer, I feel low pressure gas storage could work, since serving and carbonation pressures are mostly less than 1 bar. So one full keg at 6 bar could dispense 6 kegs at 1 bar.

The set up would be something like this, which is basically how it's done industrially (minus the liquifaction and scrubbing):

• Fermenters' blow off tube/airlock connected to a gas bag, which gradually inflates as fermentation progresses
  May need a foam separator

[*]Air compressor intake connected to gas bag
[*]As gas bag inflates, it pulls a string which is attached to a relay which in turn turns on the compressor
[*]When the bag deflates, the relay switches off again
[*]Compressor uses empty kegs as receivers in addition to compressor receiver
[*]Empty keg(s) fitted with filter/moisture seperator/regulator to reduce outlet pressure to serving pressure
[*]Free dispensing gas!

Without the compressor and bag it's still possible, but you lose the flexibility to ferment at a different pressure to carbonation. I would be mildly concerned about carryover of aromas or whatnot, but the main thing to control is the foam/blow off.

 

[crowmanz]

I think it was S.E. who posted about capturing CO2 from a ferment in a bag then used that CO2 when he dispensed from a cube.

Cant seem to find the thread though

 

[mtb]

Ultimately though it's a matter of cost (dollars and time). Yes, the dispensing gas is free, but the gear would/could cost a mint and the space and time required to maintain would be high in comparison to just getting a CO2 bottle re-filled at the LHBS.

I think daisy chaining kegs as per the OP is a good idea but storing the CO2 for later consumption sounds a bit too much effort.

 

[klangers]

Ultimately though it's a matter of cost (dollars and time). Yes, the dispensing gas is free, but the gear would/could cost a mint and the space and time required to maintain would be high in comparison to just getting a CO2 bottle re-filled at the LHBS.

I think daisy chaining kegs as per the OP is a good idea but storing the CO2 for later consumption sounds a bit too much effort.

Haha of course! If we adopted that approach, we'd never start home brewing

I would only attempt for my own engineering-geek reasons. Refilling the CO2 tank is an inconvenience more than an excessive cost.

 

[mtb]

Haha of course! If we adopted that approach, we'd never start home brewing

That is a very good point.. if it weren't for unnecessary experimentation I'd say I wouldn't get a jolly out of my kegmenters every time I see them

 

[pirateagenda]

good ideas,

I guess if you wanted to keep it simple and cheap, you could re use the gas for serving pre carbed beer by using the original daisy chain method, and filling an empty keg with the spunding valve set to serving pressure. 1 keg gas for 1 keg beer at that rate, you'd need the receiving gas kegs to be at serving temp though.

i might grab a couple of extra disconnects and capture some of the gas in a spare keg for the primary to corny at the least anyway.

 

[Benn]

haskel booster pump

Used in the SCUBA industry to move gasses around like Helium & Oxygen for storage and blending.
The savvy brewer could capture Carbon Dioxide produced during fermentation and store it in a cylinder for later use...

 

[mtb]

haskel booster pump

IMG_5459.JPG
Used in the SCUBA industry to move gasses around like Helium & Oxygen for storage and blending.
The savvy brewer could capture Carbon Dioxide produced during fermentation and store it in a cylinder for later use...

This looks like one of those huge experimental guns they give you in video games. Like the BFG from Doom.

 

[Bribie G]

Many yeasts will ferment at serving temperature. When I used to do ciders I would have a corny of cider mixed with apple cordial in the 3 keg kegmate and 2 beers. The cider would serve the beers nicely with the free gas produced.
As the cider dried out I would tip in more juice or Bickfords and away we went again.

 

[klangers]

haskel booster pump

IMG_5459.JPG
Used in the SCUBA industry to move gasses around like Helium & Oxygen for storage and blending.
The savvy brewer could capture Carbon Dioxide produced during fermentation and store it in a cylinder for later use...

That looks like a plunger pump, capable of >200 bar. Would definitely work, but would also most likely cost >$3000. Professionally I'm all good with 200 bar pressures, but would not touch with a bargepole at home. If you've ever seen a high pressure injection injury you'll know why.

 

[Grott]

Many yeasts will ferment at serving temperature. When I used to do ciders I would have a corny of cider mixed with apple cordial in the 3 keg kegmate and 2 beers. The cider would serve the beers nicely with the free gas produced.
As the cider dried out I would tip in more juice or Bickfords and away we went again.

Did any cider flavour come through with gas and effect the beer in any way?

 

[meathead]

Ive got a corny of uncarbed Rogers clone and am about to put a session IPA in fermentasaurus.
Will report back in a week or so.

 

[RdeVjun]

+1 for Bribie's method, it's low-tech but effective and needs no extra kit. Last year I had this setup running for about four months with some success (SWMBO wanted cider), IIRC just the occasional gas adjustment. You can fiddle around with your own unique perpetual cider recipe, while my conscience was warmed a bit too.

grott, i can't speak for Bribie but no, that wasn't a problem.

 

[klangers]

How do you manage the pressure with the Bribie cider/serving method?

 

[pirateagenda]

Ive got a corny of uncarbed Rogers clone and am about to put a session IPA in fermentasaurus.
Will report back in a week or so.

good stuff!

 

[Bribie G]

Didn't seem to get any flavour crossovers. It's generally a seat of the pants exercise, but I didn't get the beer too fizzy and even needed to turn on the bottle for a top up now and again. Because I have a no return valve on the gas line, just turning on the bottle actually flicks the reg needle to display the current beer-side pressure so you can see what needs to be done.