[qm3k]

Maybe this should go in the general topic category, but it has to do with oxygenating my wort prior to pitching my yeast.

I have recently switched from aerating with an aquarium pump to pure O2. I use a bottle of oxygen that I get from the local hardware store without any kind of flow meter (just the canister, a regulator, a tube, a filter, and an aeration stone).

About how long should I let the oxygen flow, and should it be a fast flow, or one that produces smallish bubbles from the stone? I simply don't want to overdo it.

Cheers!

[Joe Sr.]

You want the bubbles to come out almost as slow as possible.  If it's bubbling out the top of the wort, then it's not going into solution.

I run mine for around 60 seconds or so.  I don't really time it. Bigger beers, I run longer than smaller beers.

My understanding is that it is extremely hard to over-oxygenate.

[JT]

I found that before I had a flow meter I used way too much oxygen.  The money I saved by regulating to 1 LPM has easily paid for my meter, and mine wasn't cheap (around $70 I think). 
If you end up getting a meter, you don't want to look for one that measures too much volume.  0 - 3 LPM is perfect and allows you to easily dial in the 1 LPM desired flow rate.  If you're going to eyeball it, you should definitely see a good stream of o2 being pushed into the wort from your stone, but if the surface is boiling you're using too much! 

[theDarkSide]

About a minute on mine too, just the way Joe Sr. describes it.

[klickitat jim]

I think there's a lot of theoretical debate on this. If the bubbles reach the surface and pop, then yes that oxygen is sort of wasted. I think I pay about $9 for a bottle and they usually last me about 9 brews. So about a dollar per brew. I waste some because I want to be sure it's bubbling through the whole wort. So when I'm oxygenating I can see bubbles at the surface, but it's not blowing wort in my face. I don't time it, I just slowly move the stone around the bottom of my fermentor a couple times till I have a couple inches of bubbles on top. I'd guess it's about 45-90 seconds. I've never had a problem with this "method"

[quattlebaum]

You want the bubbles to come out almost as slow as possible.  If it's bubbling out the top of the wort, then it's not going into solution.

I run mine for around 60 seconds or so.  I don't really time it. Bigger beers, I run longer than smaller beers.

My understanding is that it is extremely hard to over-oxygenate.

+1

I also keep 5 gal star san around and start and finish the process in the starsan to insure i done leave or clog the stone with wort. They are really hard to clean if ya get wort in them.

[erockrph]

You want the bubbles to come out almost as slow as possible.  If it's bubbling out the top of the wort, then it's not going into solution.

I run mine for around 60 seconds or so.  I don't really time it. Bigger beers, I run longer than smaller beers.

My understanding is that it is extremely hard to over-oxygenate.

+1

I also keep 5 gal star san around and start and finish the process in the starsan to insure i done leave or clog the stone with wort. They are really hard to clean if ya get wort in them.

+2 - including the Star San part. I really only break out the O2 for big beers, and I kind of use a rule of thumb of 1 second per OG point - so a 1.090 beer gets 90 seconds, a 1.120 barleywine gets 120 seconds, etc. For beers even up to the 1.070's I don't bother with the O2 tank. A slow pour through my filter screens, followed by a bit of sloshing does just fine.

[JT]

I turn on my o2 before immersing in wort and don't turn it off until it is out of the wort and in PBW, to keep from getting wort in the stone.  The stone gets a quick boil in RO water before using again. 

[HoosierBrew]

I used to use O2 regularly but now I use a mix stir (until the foam reaches the top of the bucket) with a cordless drill and can't tell the difference. Even on beers up near 1.100. I'll use O2 on 1.100+ beers though.

[brewinhard]

For ales with an OG below 1.070 or so, I simply put a sanitized piece of foil on top of the carboy and swirl/shake the crap out of it for 5 minutes straight.  I get good results with this and it save me having to bust out the old O2 tank, line, and prepping the stone. 

For beers greater than this OG I only feel comfortable using the stone and O2 tank.  Anywhere from 60-90 seconds based on the OG. 

For lagers, since I pitch at around 50F, I almost always use the stone and tank just to be sure that I get enough oxygen into the wort so the yeast can ferment in a cooler environment.