Adding O2 to your ferment tank questions

Northern brewer makes an oxidation stone that uses the oxy cans at home depot. Honestly, I've had great luck pouring through a sanitized screen. I live at 6500 feet (about that anyway) and have never had a yeast under attenuate.

 

Not exactly sure if you intend to use an aquarium pump to push some air . . . if so, it tends to fall a little short of what's needed. I can't imagine air from a cannister being measurably different than outside air . . . would expect no problems from either.

Here's Wyeast's data of what to expect with O2 versus air only:
http://www.wyeastlab.com/hb_oxygenation.cfm
http://www.wyeastlab.com/hb_makingastarter.cfm

Mr. Malty also has some good guidelines:
http://www.mrmalty.com/starter_faq.php

For my starters I add pure O2 through a 0.5 micron stone. I tend to over-oxygenate then decant the liquid before pitching.

 

The difference is that the O2 canister systems inject pure O2. Fish pumps inject air, which is mostly not O2.

 

If you want to just use an aquarium pump, be aware that room air is not high in actual O2 (as VikeMan said above). You can buy an in-line filter if you choose to go this route (and yes, you should filter it).
If you want to actually oxygenate the beer you'll need an O2 canister system.

 

Are you using a stir plate for your starters? What is your procedure for making a starter, brewing, and fermenting?

Air has dust. If you are pumping through an aquarium pump, definitely use a sterile filter. Otherwise it could lead to a "funky/bad batch" as you said. It also takes much longer to get an equivalent amount of oxygen with an aquarium pump, assuming you can reach that level at all. I have been using an aquarium pump with diffusion stone for many years and have never had trouble with head formation, but I have heard and read that those protein forming compounds that make bubbles only happen once. So if you can oxygenate for 1 minute with pure oxygen or 10-15 minutes with an aerater, you can see that the diffusion stone will create bubbles that will use up much more of those bubble forming proteins with the pump. Again, I have not had a beer "underfoamed", but it is a consideration.

 

For $60 max you can get every thing you need to do pure o2. The tanks cost between $5-$10. If you brew regularly it is well worth it. Not only have my brews gotten better since using it but no more shaking/swirling my bucket for 5 minutes after a long brew day. That was one part of the process I never looked forward to.

 

All I ever do is just transfer my wort back in forth from pot to fermenter (after straining and cleaning both) til theres a nice frothy head. Effective and FREE!

 

Either method--air via aquarium pump or oxygen from a tank--can work. But pure oxygen is much more efficient.

I'm too lazy to go look this up, but somewhere in White's book on yeast he measures oxygen levels in wort following aeration by different methods. IIRC the wort reaches a peak level after only about one minute of pure oxygen, and using pumped air takes much longer, and never reaches to high levels you get with oxygen, though clearly it's still going to be beneficial. That was enough to get me to switch over the pure 02, and that's why I'd recommend it if you have a choice. But you can get by with an aquarium pump set up if you have to, particularly if you stay away from higher gravity beers.

 

In the book's data, pure O2 does not peak after one minute. It's at 9.2 ppm. After two minutes, it's at 14.08 ppm. (5.3 gallons of wort, 1 l/min flow, 0.5 micron stone.) After three minutes, it would be even higher (though the book doesn't mention that.) It is possible to over-oxygenate. Shaking, in contrast, only yielded 2.71 ppm after 5 minutes. This particular experiment didn't test pumped air.