Fill CO2 tank with yeast?

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tavernpuzzler

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Sorry if this has already been brought up and shot down, but I didn't see this idea when searching HBT.

What if you were to let the yeast ferment in a high pressure container and have that hooked up to an empty CO2 tank. As the pressure builds where the yeast are, it would also build in the tank to be filled. Everything would have to be able to handle the 1000 psi or so pressure.

A couple concerns:

1. Moisture content in the CO2 going in to the CO2 tank being filled.
2. Is there a pressure that yeast cannot survive in?


Any thoughts on the feasibility of this?
 
yeast will go dormant about 30 psi. One fellow used an old water heater that didn't leak to store CO2 from fermentation, then he had that hooked to his kegerator.
 
I believe Chris White (of White Labs) mentions that much above 15psi, they start seeing mutations in the yeast. Something to think about if you're washing yeast for reuse.
For myself, I only try and keep enough CO2 around during fermentation to carb the current beer. Anything else is the angels share (do they even like CO2?)
Also, a brand-new corny can only handle 130ish psi. My cornies are not anywhere near new condition :)
 
You're also forgetting that inside a CO2 cylinder is LIQUID CO2...

When you run out of CO2 liquid, all that's filling the tank is about 1.5 cubic feet of CO2 gas, which is basically none.

So filling a CO2 cylinder using CO2 from yeast is going to give you enough CO2 to dispense a couple of pints if you're lucky, then the CO2 tank is empty. More than likely your CO2 generator will explode once it fills the cylinder with gas, much like an overprimed bottle of beer.
 
I believe at some point, the pressure would force the CO2 into liquid form, but where in the line it begins to condense would probably be random unless you kept the cylinder being filled at a lower temp that the rest of the setup.

As long as all of the lines and tanks are rated for the high pressure I don't see why anything would explode.

...But if the yeast is going to start mutating at 15 psi and go dormant at 30 psi it doesn't much much either way. Maybe if the yeast were just used as a source for CO2, for the compressor mentioned in other threads. Their problem was that compressed air has oxygen in it which would of course be unusable in kegging.

I like the old water heater tank idea. I'd think you could dispense a couple kegs if you had it charged to 15 psi. Really, all you need is enough CO2 to carbonate and dispense 1 batch, if you capture CO2 with every batch and you might get away with not having to buy CO2 again, except for travel situations.
 
If you want to use the CO2 produced during fermentation to carbonate your beer, the easiest and most simple method by far is to ferment in a pressurized vessel (like a keg) and use a spunding valve. Set the spunding valve to 10-15 psi for the early stages of fermentation so that the yeast aren't hindered, and then turn it up to the appropriate level to achieve the desired carbonation level for the very tail end of active fermentation. This way theres no capturing and compressing and re-introducing the CO2. Each batch simply uses it's own CO2 production to carbonate itself in the fermenter. There are other aspects of fermenting under pressure that can be useful, like the lower production of esters and other byproducts. If you're interested in more info, there's an article in the HBT wiki about fermenting under pressure. There are also threads here that detail how to make a spunding valve.

https://www.homebrewtalk.com/wiki/index.php/Closed-system_pressurized_fermentation
 
Or just prime with corn sugar and run off a couple cloudy pints, then you can use whatever vessel youve decided on at 15psi for dispensing. I know it's a great DIY project but it doesnt seem easier or less expensive, IMHO.
 
I've seen people use balloons (the foil kind) for CO2 capture though.
 
Or just buy CO2. A 20 lbs tank of CO2coat me about 25 bucks to fill. It lasts me almost a year.

It's just not worth trying to capture CO2 from yeast.
 
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