Do You Use a Filter with O2 and a 0.5 Micron Stone?

I just purchased a sintered air diffuser stone and a small O2 tank. The advertised pore size in the stone is 0.5 microns. I doubt anything that would like to eat wort would like to live in a compressed tank of oxygen and 0.2 micron filters work great for sterile filtration, so I'm thinking I should be safe just sanitizing everything that will touch the wort. All of that is assuming, however, that there aren't larger unadvertised pores in this stone I just purchased.

For those of you who use pure O2 and a similar stone, do you filter the O2 or not?

I don't think there's any reason to filter pure compressed O2, it should be sterile. I used bottled O2 and a stone and have never experienced a problem.

How about the difference between medical O2 (which certainly would be sterile), and bottled O2 for torches (cheap tanks from department stores). Both safe and sterile? I've been wondering.

The guy at my local welding shop told me that the only difference between medical o2 & welding o2 is the tank.

I don't trust the welding o2 bottles. They have a label on them that states that the bottle contains carcinogenics. At least they cause cancer in California. I guess they're safe everywhere else. So, I use the filter. It may be overkill, but, how much do those little filters cost? Not much.

73Drvr said:

I don't trust the welding o2 bottles. They have a label on them that states that the bottle contains carcinogenics. At least they cause cancer in California. I guess they're safe everywhere else. So, I use the filter. It may be overkill, but, how much do those little filters cost? Not much.

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Seriously? My bottle doesn't have any kind of disclaimer like that. Lots of things (including stuff in your water heater) are known to the state of california to cause cancer in laboratory animals... still, that's unsettling. At the very least, all of those carcinogens could foul up an otherwise healthy fermentation. Neway a filter isn't going to take out carcinogens. Just beer spoilage microorganisms.

No need to filter pure O2. It's sterile and toxic to critters in very high concentrations. The welding oxygen is perfectly OK to use. It comes from the same source at the medical grade oxygen. I read somewhere that the medical grade contains a small specified amount of moisture which the welding stuff does not. I'm not certain whether that is true or not, so YMMV etc. Everything made or sold in California has the cancer warning label. Labels are cheap. Lawsuits are expensive. That's the reason.