Food Grade CO2 vs. Industrial CO2

[bleme]

The owner of the welding supply shop that I use is a homebrewer and uses the same gas/tanks.

 

[Transamguy77]

The airgas I go to only sells good grade co2, and every tank has a sticker with numbers on it to track it. I don't remember anything like that when I lived I Pa so maybe location dictates? I've also been told it's all food grade so it's all the same.

 

[Diver_Alan]

For my O2 red tanks from HD, I still use the 1 micron air filter that came with my fish tank air pump setup that I used before switching to pure O2. May not be needed but just in case...

I wonder if those can be used safely with CO2 at the pressures we serve at?

Keep in mind the obvious. Oxygen and CO2 are not the same gas.

Oxygen cones in several grades ( aviation, medical, and industrial ). Oxygen is Oxygen it is all the same, the difference is in the testing and record keeping (and price). For example aviation grade is tested for moisture while oxygen used for welding comes straight from the tank without any additional testing.

One of the differences between O2 and CO2 is that an O2 cylinder can only be filled if it is O2 clean. The presence of any hydrocarbons in a O2 tank would likely result in a flash fire and possibility an explosion. For homebrew use any oxygen will do. On the other hand CO2 can be filled into any cylinder without regard to how clean it is. The only requirement is the the cylinder be hydrostatic tested every 5 years. Testing does not clean the cylinder unless rust is present in steel tanks. If it is the rust may be removed from the cylinder. When you do a CO2 exchange unless you request food grade you don't know what was present in the cylinder before it was refilled. The gas may all be the same but anything in the cylinder before it was filled may end up in your beer.