Making your own CO2

So since the price of refilling my 5lb tank has risen to nearly $30, I was thinking of trying to capture the co2 from fermentation and use it to carb and dispense. I figure I could dedicate one of my corny kegs as a closed fermenter with the gas tube connected to a low pressure regulator, and connected to my kegs of beer after that. I figured this would be a simple experiment that could pay off well.
So any ideas or critiques would be appreciated.

Edit: I see some potential dangers with this, but I could use a fermentable simple syrup in order to prevent kraussen and potential clogs that could be linked with that.

Capture, refine, compress, store.

Only cost the likes of Sierra Nevada hundreds of thousands to implement.

CO2 reclamation for Brewing Industry.

My main question is what is your plan on getting it compressed?

No need to compress, I'm talking low pressure. Less than 100psi before a regulator, and fermentation will do to compress that. I'm thinking that would suffice to serve a keg at 10psi.

I'm not sure that a normal ferm creates a very high pressure.
What pressure can it make?

GilaMinumBeer said:

Capture, refine, compress, store.

Only cost the likes of Sierra Nevada hundreds of thousands to implement.

CO2 reclamation for Brewing Industry.

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+1

IF it was easy as the OP wants, then you'd see tons of homebrew supply stores selling kits to do it.

You need to remove all O2 from the gas (to a level of <.1%) before using it. Otherwise, you'll oxidize your beer with it. Plus, you want to filter out the aromas that are kicked out during fermentation.

You might want to look into fermenting under pressure to at least partially carbonate your brew before going to serving keg.

Holy crap. $30? I just filled mine month ago for like $10.

Interesting idea ... although I question whether it would actually be cost effective, and whether your yeast would survive to continue producing CO2.

To carb and dispense a keg, you'd have to use quite a bit of sugar. While cheaper than brew, it aint free. Plus, you have the PITA factor of doing this for every keg you want to carb/dispense and not knowing if your yeast will survive the high alcohol content of the fermentor, and soon that $30 would seem like a bargain, if only for the convenience.

... That being said, I'm curious how much CO2 would actually be produced by a simple sugar fermentor.

LoneWolfPR said:

Holy crap. $30? I just filled mine month ago for like $10.

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I think the OP needs to find another place to get his CO2 tanks filled up. Even the places that swap them out, in my area, don't charge that much. I can get my tanks filled for far less too. In line with the $10 for a 5# tank. Of course, the larger your tank, the lower the cost is per pound of CO2 (or how it appears). Such as $12 for a 10# tank. Or $17 for a 20# tank.

Look to places that also service fire extinguishers since they [often] have the means to fill CO2 tanks.

Hmm, never thought of this. Interesting enough concept but will it work?

Assuming you get 100 psi before the regulator (does fermentation throw out that much CO2?), you'd be dangerously close to the limits of a corny keg (130psi), and you'd essentially be carbing up your simple sugar solution while you go. Would the yeast survive in a 100 psi environment, and that much CO2 dissolved in the solution?

Golddiggie said:

+1

IF it was easy as the OP wants, then you'd see tons of homebrew supply stores selling kits to do it.

You need to remove all O2 from the gas (to a level of <.1%) before using it. Otherwise, you'll oxidize your beer with it. Plus, you want to filter out the aromas that are kicked out during fermentation.

You might want to look into fermenting under pressure to at least partially carbonate your brew before going to serving keg.

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Wait what!? I didn't realize o2 or oxygen was a biproduct of fermentation. In this case how does all beer not become oxidized by primary fermention or conditioning?

http://www.genre.fsnet.co.uk/brewery/co2/index.html
http://www.angelfire.com/cantina/carbonation/

frothdaddy said:

Assuming you get 100 psi before the regulator (does fermentation throw out that much CO2?), you'd be dangerously close to the limits of a corny keg (130psi), and you'd essentially be carbing up your simple sugar solution while you go. Would the yeast survive in a 100 psi environment, and that much CO2 dissolved in the solution?

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These are the answers I'm looking for. Total assumption, but I figure if <5oz of corn sugar can carb a keg with 15psi in the headspace, then enough pressure to serve it as well doesn't seem to improbable.

While you ferment, you're venting off excess CO2/gasses. IF you go and capture (assuming from the start) you'll get more than just CO2 in your containment, or into the beer. This is one of the reasons why you don't just capture the CO2 from fermentation and use it. You need to filter it, and then compress it so that you can push it into the finished beer.

IMO, this isn't a project for anyone not 100% familiar with all that's involved.

As for the previous comment about 100 psi being too close to the 130 psi listed maximum... At 130 psi, the release/safety valves will trigger. IF your keg is in good condition, it shouldn't fail. Not to say it won't, due to a flaw or damage, but I'd be less concerned about that. Besides, I've read [before] that yeast pretty much stops around 30psi. So the chances of getting even close to the previously listed 100psi target is a pipe dream (IMO).

Seriously, IF you really, really, really want to do this, research all that's involved first. Don't go into it half-assed since that could be dangerous. Although you could get closer to the results you desire by fermenting under pressure. Although, I would advise finding a better source of CO2 in your area first. With what it could cost to rig up a system to capture CO2, you could probably purchase CO2 for many years before you come even close to that level. If you can't recover/save the expense of making the system within a couple of years (<3 being my normal guide) then I wouldn't. Unless you have that much money to blow.

TheCarnie said:

These are the answers I'm looking for. Total assumption, but I figure if <5oz of corn sugar can carb a keg with 15psi in the headspace, then enough pressure to serve it as well doesn't seem to improbable.

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Using more sugar in order to try to capture excess CO2 means you'll be very over-carbonated. IMO, more trouble than it's worth.

Well I'm gonna give it a shot. At worst I ruin a batch of beer. I used to be an engineer so this really intrigues me. For me it's worth the experiment to know whether it can be done.

It certainly will work. If I remember the lecture, most yeasts can handle ~135 psi. I would definitely check out the kegs by running them up to ~100 psi. Most of my used/reconditioned kegs will relieve before the 135 psi rating. In fact, I had to go through most of my kegs to find four that can handle 60 psi for soda. One relief valve goes at 17 psi! Not a problem for beer, so I haven't replaced the valve.

Haven't done the math, sugar vs CO2, so I can't say if it is cost effective.

I bottle condition all my beer, but it seems there's a simpler way to carb your keg for cheap. Add sugar syrup to he meg before you transfer and let it naturally carbonate, the only CO2 you use would be to push the remaining beer out of the key.

If you naturally carb your kegs you'll make that 5# cylinder last for a really long time.

There have been a few threads discussing this idea over the years. Many very smart people have chimed in, and nobody is even remotely close to an economical way to capture and store quality CO2 from fermentation on the homebrew scale.

It's very easy to carbonate your beer using the CO2 produced during fermentation though, and many microbreweries use this method to at least partially carbonate their beer. All you need is a fermenter capable of handling pressure, and a spunding valve. When fermentation has slowed way down, crank the pressure up on the spunding valve up to correspond with the fermentation temp and desired carb level. When fermentation is complete, you'll have carbonated beer ready to be transferred to serving kegs.

One of the main reasons commercial CO2 capture systems are so expensive is the filtration aspect. There are a lot of nasty things being thrown off during the peak of fermentation, when the most CO2 is being produced. There are more gasses than just CO2 being released, as well as impurities that cling to the gasses. I'd venture that most of us have had at least one fermentation that released some pretty toxic smells from the airlock at some point. Unless you want beer that smells and tastes like rhino farts, you'll probably want to filter out these impurities before trying to use the gas for serving your beer. Or collect somewhat cleaner CO2 from a later stage of fermentation, which will yield much less gas. Also, the higher the pressures, the more stressed the yeast will be, and the more of those nasty byproducts they will create.

I can't even begin to remember the details, but a guy did this on the old green board, maybe 6-8 years ago?

If I recall he used a water heater (your water supply is around 80 psi, and they fail much higher) with success. You could try and search the archives, some old threads might still be around.

I work for a company that makes industrial gases like oxygen, nitrogen, argon, hydrogen and carbon dioxide. Trust me when I say you can't do it on a homebrew scale. 100 psi is nothing to be messing around with. You're basically building a pipe bomb. That's a lot of pressure, and I don't think you could build that kind of pressure without compression equipment. Plus, there is a lot of other stuff coming out of your fermenter than just CO2. I'm sure you've smelled it. CO2 is odorless, so that's not CO2 you're smelling.

LoneWolfPR said:

Holy crap. $30? I just filled mine month ago for like $10.

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+1. Costs me the equivalent of about $10US.

Is there anywhere else you can get a fill? $30 is nuts for 5lb tank.

david_42 said:

If I remember the lecture, most yeasts can handle ~135 psi.

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can handle being in a 135psi atmosphere without cell death, yes. being able to produce (more) CO2 under those pressures? definately not.

yeast stop producing CO2 around 30-40psi regardless of nutrients or alcohol percentage. you will need a pump if you want higher pressures.

TheCarnie said:

These are the answers I'm looking for. Total assumption, but I figure if <5oz of corn sugar can carb a keg with 15psi in the headspace, then enough pressure to serve it as well doesn't seem to improbable.

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Okay but, you are proposing a dual vessle closed system. One vessle for fermentation, another for CO2 capture. So, lets assume the capture vessle does contain 15psi CO2 and other fermentation byproducts (not unlike bottle carbonating).

Hook that vessle up to another with no psi and at most you will get s'think like half (7psi) once the available CO2 goes into solution and the two tanks meet equilibrium.

At 40*F you'll have 2.01 volumes and at 60*F you'll have 1.23 volumes.

Furthermore, since pressurization will be directly correlated to flexural properties of the tank one the stress is relieved from teh tank walls (since you don not CO2 in a liquid state to cause repressurization) you will likely have less than 7psi once the two systems are connected and equilibrium is attained. meaning you'l likely not see even 2 volumes at low temperatures.

This may be off track for this thread, but here's my question, especially for phyrst:

A friend of mine works for coca-cola as a tech setting up soda dispensing stations, he also has experience setting up beer dispensing and cooling systems. he said that the co2 used to fill bottles is generated from a machine that get's co2 from the atmosphere. Certainly theres a whole lot more to it than that, but what is the process for generating co2, and could a system be built at a consumer level (for example, could a brew club pool their cash and build a co2 generator)

Check out CO2 membrane separators work off of compressed air. I save some co2 as I use a kicked keg to vent newly filled kegs. our co2 cost is way out of wack shop around you pay 2 times what most of us pay