what kind of co2

Is there a differance between foodgrade co2 and the industrial grade co2 ....and does it make a differance? thanks for any help!!

Food grade is pure CO2 (filtered, etc.), industrial can contain some oils or impurities. I don't think it really matters which one you use; it should not affect the quality of the beer or your health. I get mine filled where it is cheapest (currently a fire extinguisher company). FWIW - Most CO2 you will find is the exact same that is used in the beverage industry (CO2 is CO2).

thanks alot

The difference has to do with the almighty buck! A place that sells "food grade" CO2 must pay for certifications to do so. Welding CO2 must be just as pure as food grade for the welds to good. Welders would never tolerate oil in there shield gas.

Ditto-- I get mine filled at a fire extinguisher supplier-- In fact, got it filled today. I've also had it filled at welding suppliers, and I've never seen any adverse effect on my brew.

In short, don't worry about it. CO2 is CO2 (as was already said).

I believe there is a difference in the tanks, though. Food grade tanks are supposed to be glass lined in case of backflow getting into the tank. This way, it won't corrode and explode if the backflow goes undetected.

FlyGuy said:

I believe there is a difference in the tanks, though. Food grade tanks are supposed to be glass lined in case of backflow getting into the tank. This way, it won't corrode and explode if the backflow goes undetected.

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Hmm. Not sure... I've never had the issue myself.

Tagamet for CO2 tanks, I guess? got to prevent that reflux into the tank...

I doubt it. For one thing, tanks do expand and contract, and would bust the glass.

Plus, has anybody ever seen a tank labeled 'for food service use', or 'NOT....' . Anybody ever buy a tank from a HBS that had a sticker on it....

Plus, a couple years ago I heard that Medical oxygen is more polluted than industrial stuff. Seems even sick people are more tolerant than industrail processes.

Do any of you use a filter of any type between your CO2 and your kegs? Is there an inline filter available, that might catch "nasties" before they can get into the keg?

At my bar we use the same tanks/co2 that I use at home, which I fill my tanks via AirGas.
AirGas caters to welders and I love getting ripped off everytime I refill, they charge me like 29 for my 20lb and they are a**holes and won't even touch my 50lb cause they think it is stolen (but thats another thread).

So...It doesn't matter, like said before CO2 is CO2. But good question, it has crossed my mind before as well as a lot of others.

LouT said:

Do any of you use a filter of any type between your CO2 and your kegs? Is there an inline filter available, that might catch "nasties" before they can get into the keg?

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No, you don't use a fliter of any kind. You use a check flow valve. This valuve allows Co2 to flow out but nothing to flow back in. This also protects your regulator from being damaged.

How would beer get pushed basck through the CO2 lines and end up in your regulator? If you remove the CO2 tank from your regulator while the regulator is hooked up to the keg, the pressure in the keg will try to escape through the air line, since there is no longer any pressure there to keep it in. A check valve 'traps' the pressure there-- the line will still have co2 in it under the same pressure it was puyshed there at before the tank was remvoved.


In my experience, most of the time if you have a ball valve in your gas line (a valve between the regulator and the gas line) there is a flow check built into the ball valve.

kornkob said:

In my experience, most of the time if you have a ball valve in your gas line (a valve between the regulator and the gas line) there is a flow check built into the ball valve.

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You have to be careful and check this though. My regulator (a Micro Matic) had barbed ball valves without check valves. (I knew this when I bought it, but I wanted to put ball valves with flare fittings on them anyway that had checks built in.) For commercial kegs it's not an issue since there is a check valve in the Sanke tap, and I don't think you're supposed to have more than one check valve in a line. Soda keg fittings don't have checks, though, so you need to put one in-line somewhere.

I use the shutoff/check valves with flare fittings that Northern Brewer sells. I have found the check feature of these valves to be unreliable so I installed these inline check valves from US Plastic Corp



If you don't connect your gas in line to the beverage out post on the keg there is no way that beer can get into your regulator. There really is no valid reason to do that. I don't feel that the beer carbonates any faster with the CO2 bubbling up from the dip tube.

For the cornie kegs the lines would have to be reversed to push beer into the co2 line which means you would have to screw up the barbs on the fittings and screw up the fittings and connect everything wrong and have an empty co2 tank. Or somehow get negative pressure in the co2 tank and then have the cornie keg on its side so that the beer could be pulled into the tank through the the line and the regulator. And if you use the sanke kegs it has a check ball and if the check ball were to go bad it would likely leak out of the fitting and not the co2 line.
So I think No check ball or filter needed!

Thanks for clearing that up. Just had a concern about any nasties that might be in a tank of CO2 - the exchange tanks have unkown histories...

Now, I've never had this happen on my balllock system but I watched it happen to a coke system at a non-profit event once.

They ran out of CO2 and decided to change the tank. After closing the valve on the tank they unscrewed theregulator from the tank while still hooked up to the chain of kegs. Shortly thereafter there was coke backing into the gas line.

Now I can't speak to how the system was configured (although I never drank any of that soda-- the lines looked positively disgusting) so it could be that they had something hinky about the kegs or the daisy chain of kegs.

I've switched to clear lines so that I can monitor if this has ever / will ever happen.