Homemade CO2 production ?

[brewman !]

Has anyone given any thought to producing their own CO2 at home ?

Fermentation creates lots of CO2 and it will do so to dangerously high pressures.

Corny kegs are rated to 120 PSI. The pressure relief valves on corny kegs are usually set to 100 PSI.

BTW a safe way to pressure test a vessel is to fill it with pressurized water because water doesn't expand much if something breaks. Air and other gasses do expand a lot and thus their "explosion" is violent. Anyway... I digress...

One can buy a large stand alone air tank rated for 120 PSI quite inexpensively. I've got a 12 gallon tank that I paid $40 for.

So... what if one took a corny keg and dumped some sugar and water and yeast into it and got it starting to ferment. And then one connected a 12 gallon air tank to the keg and let the generated CO2 fill up the air tank ? Maybe purge it out once and then fill it for good. The result would be a tank full of high pressure CO2.

Then, when one needs to carbonate or rack using CO2, one has a CO2 source ready to go.

One would have to make sure the air tank didn't have any smells to it that would smell up the CO2 and thus the beer. But how do we know that the CO2 cylinders we have now don't have this problem ?

I think the math for determining how much CO2 one could get from the 12 gallon air tank looks like this. (Its late at night as I write this and I'm going off the top of my head...) I think the pressures need to be in absolute terms. Basically P1V1= P2V2.

So...

Volume of CO2 that could be used before dropping to 15 PSI:
12 gallons x 115PSIA = (x+12) gallons x 30PSIA x = 34 gallons of CO2 at 15 PSI.

If a keg is carbonated to 3 volumes at 15 PSI, then a 5 gallon corny keg would need 15 gallons of CO2. So 34 gallons / 15 gallons/keg = 2 kegs.

Carbonating to a lower pressure or lesser volumes would increase the number of kegs that could be carbonated.

As far as racking, the volume of CO2 that could be used before dropping to say 3 PSI:
12 gallons x 115 PSIA = (x+12+ gallons x 18 PSIA x = 64.66 gallons.

Racking would require 1 volume of CO2 or 6 gallons per batch for me, so one 64.66/6 = 10 carboys.

So... is this feasible ? Next question becomes, how much sugar does it take to generate 12 gallons of CO2 at 100 PSI ? I guess we need the density of CO2 at room temp and 100 PSI. I doubt it would be 1 pound. And then what is the ratio of the weight of CO2 produced to sugar consumed ?

Any chance a pound or two of sugar would produce enough CO2 to fill the 12 gallon air tank to 100 PSI ? I kind of think it would because its the same amount of sugar that one would add to 2 kegs of beer if kraeusening. Only difference is that it ferments in the corny and goes into the tank and then the beer instead of fermenting directly in the beer.

Comments ?

Is this worthwhile ?

I for one wouldn't have to spend $100 on a new certified CO2 tank and I could sell my high pressure regulator too. I've already got a 12 gallon air tank and an air compressor regulator. (Of course I would have to check that they are clean...)

Refilling the air err... CO2 tank could be as easy as throwing water and sugar into a corny and letting it sit for a few days. No more running to the welding shop during business hours to get a refill. And I could fill a few smaller containers so that I could easily serve keg beer at parties without lugging my 20 pound tank with me. (I guess I could do this from a 20 pounder as well.. )

Hmmm....

 

[Ol' Grog]

First, you going to have to find a way to pump the CO2 into a tank anyway. Second, how are you going to insure a way to keep air out of it? You surely don't want to force carb the brew with any % of air in it.

 

[brewman !]

First, you going to have to find a way to pump the CO2 into a tank anyway.

The fermentation in the corny will produce high pressure CO2. There shouldn't be a need to pump anything.

Second, how are you going to insure a way to keep air out of it? You surely don't want to force carb the brew with any % of air in it.

I think you'd have to fill the air tank one or more times and to purge out the air. On the fermenting side, get the fermentation started without the tank and leave it us all the O2 in the keg. Once its going good, attach the hose and purge it, then hook up the air tank.

 

[Aabrewedxxxx]

You have a good idea.

Your CO2 tank can only have as much pressure as your fermentor. So if your fermentor builds up 100PSI your tank will build up 100 PSI. They will always equalize.

However there is a way to make 200PSI or more in your tank and much less in your fermentor:This would be done by manipulating the temp.

If you remember taking chemistry. Volume of gas is determined by two components: Temp and pressure. If the temp is high then the gas expands. If the temp is low then the gas contracts. In essense a CO2 tank at 100PSI at 10F will have much more CO2 than a CO2 tank at brewing temp. So if you were to fill a tank at 100PSI at 10F when you bring the tank BACK to brewing temp the PSI will be much higher in the tank.

Idealy you would want liquid CO2 in your tank and NOT in your fermentor.

The boiling point (or liquifing point) of CO2 is around -200F with the help of highpressure that temp can go up significantly.

So the question is, "how do you liquify CO2 int he tank but not hte fermentor while keeping both tank and fermentor at the same PSI?"
The answer would be to put the tank in the freezer and the fermentor OUTSIDE of freezer. The CO2 Outside of the freezer would be warmer then the CO2 inside the freezer. And because there is equal pressure in both tanks the CO2 will be at a higher concentration in the Tank. So when you remove the tank from the freezer and return it to room temperature the CO2 will be more willing to expand and the CO2 will go to a higher PSI.

You know what would help you: A freezer.
Keep the Corny next to the fridge, run the CO2 line to the freezer with your tank sitting inside.

The tank won't explode because it can hold LIQUID CO2. I am not sure if you have enough pressure and low enough temp to liquify the CO2 but it will be pressureized enough to carbonate AT LEAST a 5 gallon brew.

Matter of fact if your fermentor could handle high enough pressure you can carbonate your beer with the same CO2 made from its fermentation!

Edited to add:

I -gotta- try this.
Oh and by the way. MAKE SURE YOUR GASSLINE CAN HANDLE THE HIGH PRESSURE. And make sure the regulator is removed when you fill your tank.
Good luck!

 

[Mikey]

You might find that the yeast do not enjoy a high pressure environment and will refuse to cooperate. I believe somewhere around 2 atmospheres is the limit.

 

[user 4295]

Also, CO2 is not the only thing produced during fermentation. There are quite a few compounds that escape during fermentation along with the CO2. The big breweries that use the CO2 produced during fermentation to force carb their beers use an elaborate scrubber system to remove all the unwanted compounds.

John

 

[olllllo]

Here is a CO2 scrubber in action at the Point Brewery in Stevens Point WI..

 

[Orfy]

I think I'll stick with my soda stream and paintball bottles.

 

[olllllo]

david_42 does something with soda water and uses the water sytem pressure in some way. I couldn't quite figure it out. Hopefully he'll re-explain this again. Most times he'[s three steps beyond me. It must be his idyllic, pastural, and contemplative environment.

It's in this thread.

https://www.homebrewtalk.com/showthread.php?t=14834

By the way, I think you've convinced him that you're going to blow yourself up (based on another thread) so I'm curious as to whether he'll respond.

 

[Aabrewedxxxx]

The same CO2 that you sugar prime your beer with has the same "bad" compounds released as are released durring primairy fermentation. I really don't think it matters if you use the FLAVORED CO2 to carb your beer. if anything it would add character to the beer.

 

[brewman !]

So if we accept Adrian's argument, does that mean that home made CO2 is viable ?

Does anyone know at what CO2 pressure yeast stop fermenting ?

 

[olllllo]

One of the things that is scrubbed out of CO2 is moisture and you know what warm, moist, nutrient laden air begets.

 

[brewman !]

Thinking out loud. My shop air system has a moisture absorber built into it. Just pellets of some sort.

 

[Brewpastor]

I think paying for good, pure CO2 is worth it. Methane gas is not something I want to put back into my beer. Think about how your fermentation smells. Do you want to put that rotten egg smell back into your beer?

Yeast does stop working under pressure, but I don't remember what it is. It is, however, well under 100 PSI!

 

[Orfy]

http://probrewer.com/resources/library/bp-healthyyeast.php

Carbon dioxide can build up quickly in yeast slurry, and if kept under pressure will cross the cell walls and kill yeast cells. Pressures over 35 psi can be toxic to yeast, and soda kegs are rated over 100 psi. So if you use these kegs, shake and vent pressure regularly, at least once per day.

 

[brewman !]

I think paying for good, pure CO2 is worth it. Methane gas is not something I want to put back into my beer. Think about how your fermentation smells. Do you want to put that rotten egg smell back into your beer?

I don't know how this got started on this site, but beer should not be generating sulfurous or methane type gasses ! I was reading over in the apfelwein thread how people had fermentations going that stunk up the house. There is something wrong when that is happening. I've fermented 10 fruit wines made directly from fruit and I've never had a fermentation that didn't smell downright nice.

My apfelwein is now fermenting. I smelled the air lock and it is apple-ishous.

If yeast produced such vile and foul gasses and odors, how does krausen carbonation ever turn out an acceptable product ?

OK... back to the yeast fermentation... does the yeast die at higher CO2 pressures or just go dormant ? Here is what I am thinking. If the yeast kind of auto regulate their CO2 production, one could just put some sugar water and yeast in a corny with a regulator and leave it behind the kegerator as the CO2 supply for the kegs.

When the pressure drops the yeast would kick into action. When the pressure gets high they would slow down. The fact that they auto regulate seems to be a plus in my mind. One could have a corny with 50 PSI of CO2 in it ready to go at all times.

I'll have an empty corny in the near future. I think I am going to do some experimenting.

 

[Orfy]

.The cell walls get destroyed. It kills them/

Poor yeasties, they are our friends. DON'T ABUSE THEM!!!

 

[Torchiest]

Most ale fermentations smell fine, but some strains of ale yeast produce a slight sulphur aroma and taste which eventually fades. However, I believe lagers produce a significant amount of sulphur in the outgassing.

 

[Brewpastor]

The reality is that alcohol is only one fermentation by-product. Methane is another one and it doesn't have anything to do with brewing techniques. It is a product of fermentation which also produces Acetone and a few other nasties. It is in there, it isn't a myth, but fortunately it is not the dominent flavor or aroma.

 

[Cheesefood]

It's only about $20 to get a tank filled, and that'll last you quite a while.

Here's an interesting idea though: My LHBS also sells supplies for homegrowers and recommends making an open-fermentation super-starter as a way to add CO2 into your grow area without purchasing a tank system. If any of you are homegrowing, think about putting yoru blow-tube next to your plants. They'll love it.

 

[olllllo]

Someone ever on brewboard is doing this and it involves an old water heater and enough copper pipe to plumb a studio apartment.

If this looks efficient to you and you feel like distilling the 36 page thread, give us a report back:

It's a 50-gallon hot water heater tank. Holds about 2.4 pounds of CO2 at 20 psi.

http://www.brewboard.com/index.php?showtopic=7848

I don't think he's addressed the sanitary aspects of it, but then again his name is oldfart.

 

[Brewpastor]

It's only about $20 to get a tank filled, and that'll last you quite a while.

Here's an interesting idea though: My LHBS also sells supplies for homegrowers and recommends making an open-fermentation super-starter as a way to add CO2 into your grow area without purchasing a tank system. If any of you are homegrowing, think about putting yoru blow-tube next to your plants. They'll love it.

They have the same set-ups for aquariums that have real plants in them.

 

[Hopfan]

It's only about $20 to get a tank filled, and that'll last you quite a while.

Here's an interesting idea though: My LHBS also sells supplies for homegrowers and recommends making an open-fermentation super-starter as a way to add CO2 into your grow area without purchasing a tank system. If any of you are homegrowing, think about putting yoru blow-tube next to your plants. They'll love it.

Hmmmm...Using CO2 to help my homegrown. Sounds like a novel use to recirculate CO2 back into my system, in a roundabout way.

 

[brewman !]

The reality is that alcohol is only one fermentation by-product. Methane is another one and it doesn't have anything to do with brewing techniques. It is a product of fermentation which also produces Acetone and a few other nasties. It is in there, it isn't a myth, but fortunately it is not the dominent flavor or aroma.

Nope... yeast + water + sugar = alcohol + CO2.

http://en.wikipedia.org/wiki/Yeast

The products you mention come from the dying yeast. Proper yeast selection and racking practices will largely eliminate those off gasses.

I was shocked to hear of many people describing sulfur odors in their apfelwein fermentation. The winemakers community knows this is the sign of trouble and not an ordinary brewing occurrence.

 

[Brewpastor]

Nope... yeast + water + sugar = alcohol + CO2.

http://en.wikipedia.org/wiki/Yeast

The products you mention come from the dying yeast. Proper yeast selection and racking practices will largely eliminate those off gasses.

I was shocked to hear of many people describing sulfur odors in their apfelwein fermentation. The winemakers community knows this is the sign of trouble and not an ordinary brewing occurrence.

Nope. Try distilling with a refracting tower and see what you collect.

http://homedistiller.org/

Perhaps in a perfect fermentation enviroment only alcohol and co2 are produced, but in the real world this does not happen. My point is they scrub CO2 for a reason.

 

[olllllo]

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[brewman !]

..........

 

[Aabrewedxxxx]

If you take your bucket fermenter, fill it with beer, seal the top on, seal everything else, the bucket will expolode rather violently before the yeast will stop fermenting.

So whatever PSI yeast stop fermenting at it would be safe to assume that in theory it is in fact possible to semi fill a CO2 tank well enough to carbonate and dispense 5 gallons out of a corny. So long as you keep your tank in the freezer and your fermentor outside of the freezer. This works out great. While your beer is fermenting in the fermentor your corny can be producing the CO2.

because the tank is in the freezer and because CO2 boils at -200 and water at 214 the air (and water) that has bad smells and unfavorable compounds will liquify and fall back into the fermentor without even reaching the tank except with maybe initial fermentation.

And if worse comes to worse you could sugar prime the beer in the corny and then attach the CO2 to maintain pressure inside the keg. And if you want to avoid the smells attach a carbon filter to your airline. But if you are going to go this far might as well just pay the 4-5$ to fill the stupid tank.

 

[olllllo]

TABLE 1
Analysis of the combined CO2 fermenter output produced
the following volatile composition. (Combined carbon chain
lengths in parenthesis; concentrations in ppm).
Alcohols Ethanol (2) 1447
Propanol (3) 0.50
Isobutanol (4) 1.12
Amyl Alcohol (5) 2.1
Isoamyl Alcohol (5) 5.0
Esters Ethyl Acetate (4) 22.0
Isopropyl Acetate (5) 0.062
Ethyl Propanoate (5) 0.167
Isobutyl Acetate (6) 0.348
Ethyl Butanoate (6) 0.092
Isoamyl Acetate (7) 12.4
Aldehydes Acetaldehyde 9.4
Ketones Acetone 12.7
Sulfides Hydrogen Sulfide 3.6
Dimethyl Sulfide 11.5

http://www.mbaa.com/techquarterly/Articles/2001/38_4_235.pdf

 

[lifefermented]

I calculated the amount of CO2 produced for a 5 gallon/ 18.9 liter batch for various gravities and attenuations and plotted the results here. I also explain the math behind the plots in the post as well. But as others have pointed out, the pressure issue is a problem, as CO2 is toxic to yeast. You could easily solve the moisture issue with a desiccant (calcium chloride is actually a pretty good one), but the other impurities might be problematic, especially if you are only fermenting sugar. The lack of nutrients, normally present in wort, would certainly stress the yeast.

You could perhaps pressurize a tank by venting your fermentation vessel into another sealed vessel, like another bucket, with a small electric compressor on the inside. I have one that would fit in a 5-gallon bucket with a maximum pressure of 110 psi. You could mount a quick-connect outlet with some sort of bulkhead fitting which would output into your pressure tank through the CO2 collection bucket wall. You could put the carbon filter inline after the compressor, and the desiccant in the tank with the compressor.

That said, I would just buy the CO2.
- Dennis, Life Fermented Blog

 

[manesso]

1

 

[manesso]

1

 

[manesso]

Beyond this question about creating co2 for carbonation.
I am also an avid Gardener and I have a greenhouse. As some of you may know using co2 in the greenhouse has become quite common and can double the growth of your vegetables or most of whatever your growing.
Commercial greenhouses now buy and pump in liquid co2 or burn natural gas to make their own and increase atmospheric levels at 334 parts per million to well over 1000 depending on each plant.

Soooo , In a greenhouse that's say 10ft by 10ft and for simplicity say 10ft high. How many primary fermentations would I need to have going to reach a 1000 parts per million. The heat produced by the would be a bonus. In theory the increased production could be used for future fermentations .. the Co2 could also be piped in from elsewhere . Any thoughts are appreciated .