O2 flow for "Oxygenation Kit 2.0"?

This is a tough one. Oxygenating your wort is dependent on flow rate (typically liters per minute), size of your oxygen bubbles (effects rate of diffusion) and of course time. In Yeast the authors published how much oxygen is absorbed based on these factors. In your case two of these variables are unknown.

My only suggestion is you want the smallest bubbles possible distributed throughout the wort. It's a guess, but 45 seconds is probably on the low side (it's OG dependent). Suggest you error on the "too much" side rather than too little.

FWIW, a decent oxygen regulator that measures flow rate is under 20 bucks on Amazon, less on eBay.

 

My advice is to not make Oxygen injection too complex. Though as a homebrewer I appreciate our need to make everything a project.

I have had the opportunity to measure O2 saturation in wort with some expensive Dissolved Oxygen meters and I can tell you any minor adjustments you make to flow are not making much difference. At all. Most of the oxygen you are injecting is being lost to atmosphere anyway. All those bubbles rising to the top of the wort? That is gas escaping into air and not being dissolved into liquid. It only costs a few cents to get complete saturation. Half a dollar at most.

Completely not scientific, but 45 seconds to a minute at a moderate to low flow will get you about as much oxygen as you can achieve. My meter was getting well above 20 mg/L while injecting but as soon as the gas is turned off the levels drop to somewhere around 12 mg/L if I can recall. I just keep the injection low enough to not create too many surface bubbles and slowly move the wand within the wort.

Also, if you are not injecting oxygen into cold wort, you should. Don't bother if you have not achieved yeast pitching temp. And you definitely want to use a stone. 0.5 micron is recommended.
Cheers.

 

A commercial O2 tank is kind of a PITA. You do want to consider the safety of having explosive gas in your dwelling, and it needs to be kept clean, well separated from any ignition sources, chained to the wall, requires a high pressure specialized regulator. You can't just put a cylinder in your car for exchange. Not sure a Air Gas or PraxAir would even sell you one. Don't know, but it sounds like a head ache. No thanks. That's just one guys opinion.
@PortLargo is the resident compressed gas guru. He may have more insight. Probably.

Cheers.

 

I do the same thing you're doing Geel and have been wondering the same thing as well. I turn the valve until the flow is just vigorous enough to not make the wort bubble up and overflow out of the carboy (sort of challenging actually, but I'm getting better). I got mine on MoreBeer and I believe they recommended oxygenating for 1-2", so I'm usually in that range.

 

Couldn't agree more. Second hand medical oxygen tanks are the way to go. Here's what's out there. I find the type E tank at flea markets and garage sales regularly. I believe these are from medicare patients who get them for free and at some point no longer need them (try not to think too much about that). This is also the type tank you see mounted to wheelchairs in just about every hospital in the country. You can also find them on Amazon or eBay, but shipping is usually as much as the tank.

A Type E holds 680 liters at just over 2000 psi. If you figure three liters of O2 per batch (including starter) you are set for well over 200 batches. One of my E's is down to 400 psi, or about another two years for me. The smaller tanks work just as well, just have reduced quantity.

Here's the regulator you want:

It fits any CGA870 valve (types A - E). The black knob on the left sets the flow rate (adjustable, usually around 0 to 15 liters per minute), the barb is for your tubing. You don't really need a wand, vinyl tubing over a 0.5 micron stone works (less than 10 bucks) and is stiff enough to reach the bottom of the fermenter. Toss the tubing right before it starts to look bad.

Two caveats: 1. Oxygen is regulated in many states. In Florida it's unregulated, just like filling up the tank in your car. Other states are serious on having a doctor's prescription. Welding oxygen doesn't need a scrip, but they usually don't have the 870 connector (called a three-pin connector). 2. Tanks have to be hydro-static tested every five years, cost is around $35. I don't bother to test mine, it's cheaper to just pick up another tank at a sale (often full) and usually get another reg in the process.

Medical tanks are safe for home use, mine lives in the utility room. Just don't use them for target practice over toss in an open fire and you'll be fine.

Interesting to get your measurements, pretty much supports what the theory says. For the OP, there's a little bit more to the science of injecting oxygen . . . PM (or is it BM?) me if you'd like more nitty-gritty.

 

That is awesome and good advice as usual. Thanks.

I do think you mean to say THIS is what you want.

Ah, these beauties are injecting oxygen into your local toxic plume. All sorts of critters love oxygen and eat it up. Yeast. Soil microbes. You and me. Just gorgeous really. All the pure O2 any brewer could ever dream of...

Cheers.

 

I just inject O2 for about a minute (minute and a half for big beers) with the flow just enough that bubbles just ripple the surface. Always works well for me with strong, healthy fermentations.

 

Did that kit come with a in-line filter. If not you may want to get one. I read those red oxygen tanks are not the cleanest but who knows.I think the filters are mostly used to keep the stone clean.

 

You guessed right!

 

I aerated a beer before pitching last night and had the chance to measure DO with a multi meter I was borrowing from the lab I work at.

I aerated using a disposable tank, Anvil aeration wand (which I think the stone is 0.5 micron?) and the regulator set to the lowest setting where the bubbles are pouring out, but no higher.

One minute and 20 seconds got me to exactly 12.00 ppm DO. The beer I was aerating was 1.056 OG.

This is but one data point, but it gives me confidence for future aeration that I am at least getting into a really good DO ballpark by going low for a minute +. Also, I find if you go any higher on the flow rate you will spill foam out of your carboy before a minute is up anyway...

 

Thanks for the informed feedback. Of interest (at least to me) would be the DO before you started the O2. Theory says it should be close to zero but you never know what those little oxygen molecules are up to.

BTW, your measurement correlates well with White/Zainasheff, they publish 9 ppm after one minute of 1L/min (into 20L of 75F wort) and 14 ppm after two minutes.

 

That is a good question, it never occurred to me to measure before aerating. I would think that after the boil you would be pretty close to zero, but I wouldn’t stick a sensor in near boiling liquid, and by the time it was getting cool enough, slight amounts would be starting to dissolve in the wort just through air pressure, but it’s gotta be negligible right?

In my case I did a vigorous whirlpool and transferred my wort via siphon to the fermenter, although not with any extra splashing or aeration.... but how I got from post boil to just before hitting it with O2 definitely makes some difference in my final concentration. If I have the meter around the next time I brew I’ll check the DO conc just before I transfer to the fermenter.