Oxygenated question

[Grundysidemount]

Hey everyone,

I am a technical scuba diver and always have bottles of 100% oxygen at the house.

I hooked an air gun to my tanks and added a hose to drop in down at the bottom of the fermentor.

My question is simply, how long do I pump it in for. I can add a stone to the end but dont think its necessary.

Is this a big difference from just shaking up the fermenter.

I also have bottles of 50% oxygen, if this is a better route.

 

[RM-MN]

You want to create bubbles that have a large surface area for the volume and that means tiny bubbles, like you would get from an air stone. Without that it will take much more oxygen to get the amount wanted dissolved. Without an dissolved oxygen meter we all are just guessing on how long to add the oxygen but I'd probably suggest a minute to maybe 90 seconds without an air stone and maybe 30 seconds with one.

 

[Dland]

I usually put O2 though a stone at .5L/minute for a 3-5 mins. Maybe that is too much, but seems to work OK. Maybe I'm wasting O2?

 

[mongoose33]

I do 60 seconds with an air stone; I'll move the stone around the wort as I'm aerating it. I have a wand so it's easy to do that.

So, @Grundysidemount there you have it--three definitive answers.

But @RM-MN is right, you should get a stone. Here's an example of one: https://www.morebeer.com/products/oxywand-05-micron.html I have one of these, it works fine for me.

 

[cswant88]

With a 2 micron stone, I do 60 seconds in a moderate gravity wort, up to 2 minutes for a big beer. I don't have a gauge so I don't know the flow rate. I turn it up until bubbles just barely start breaking the surface.

 

[Grundysidemount]

With a 2 micron stone, I do 60 seconds in a moderate gravity wort, up to 2 minutes for a big beer. I don't have a gauge so I don't know the flow rate. I turn it up until bubbles just barely start breaking the surface.

What do you mean by moderate gravity. Sorry still a rookie in all this. I am assuming you mean a specific range of OG, but what's that range?

 

[Qhrumphf]

You absolutely want a stone. Otherwise bubbles just rise to the surface, don't dissolve, and foam a bunch, which is detrimental to head formation/retention later on.

I don't know if it works the same way with O2 as it does with CO2 (I presume it does but gas physics is not my strong suit), but large bubbles of CO2 can actually drive dissolved CO2 out of solution. If it indeed works the same way, a lack of a stone might actually work against you.

But if nothing else the stone is still far more efficient.

You can attain a DO meter for relatively inexpensive ($100 give or take) that'll read accurately enough for wort oxygenation purposes. Milwaukee sells one for sure, and others certainly do as well. (As long as you're not intending to use for oxidation prevention cold side, or presumably hot side as well, where a sensitive enough meter would run a few thousand $ for even a cheap model).

 

[cswant88]

What do you mean by moderate gravity. Sorry still a rookie in all this. I am assuming you mean a specific range of OG, but what's that range?

I don’t really have any hard numbers or chart I abide by, I probably should, but I don’t. One day I’ll get an oxygen tank with regulator gauge and get consistent with it. Generally, I do 60 seconds as I described up to say 1.065, then from there I’ll give it some more. 90 seconds for 1.085, full 2 minutes when it gets up to 1.100.

I try and aim for “enough” without reaching “too much”. I can’t tell you what ppm of DO any of that will give you, it seems to work for me. Someone else may have an equation for calculating ppm with reasonable accuracy. Keep it at 2 minutes or less and I think you can be reasonable sure you aren’t poisoning your yeast with toxic levels of oxygen. Use a stone, large bubbles float right to the surface and don’t get dissolved into solution. I like the 2 micron stone, 0.5 micron clogged a lot and was frustrating for me.

 

[mongoose33]

What do you mean by moderate gravity. Sorry still a rookie in all this. I am assuming you mean a specific range of OG, but what's that range?

There's no hard and fast rule, but 1.040 to maybe as much as 1.060 would be moderate, anything above 1.060 high.

With a "big beer", i.e., one with a high gravity, you'd want to oxygenate at the start, and then about another 12 hours later, as you'll need some pretty good yeast growth to get the fermentation to proceed to a low final gravity.