Oxygen regulator flow rate

[caseyodell]

I recently purchased an O2 regulator and would like to know a good rule of thumb for liters/minute for 5 gallons of beer. After reading all the threads and calculation on the subject, I'm really confused. The best I can tell is that .5 or 1.0 liters/minute for 60 seconds is sufficient. Can someone comment on this flow rate?

 

[IslandLizard]

I'm using 0.5 liter per minute for 2 minutes. That's with a 0.5 micron stone on the bottom of a 6.5 gallon bucket, stirring the wand around a bit. The wand is a spare dip tube from a keg.

At higher flow rates I see bubbling on the surface which is likely for the most part oxygen that didn't make it into the beer. I try to limit seeing those.

 

[Dolomieu]

Like stated above, I try not to have any bubbling at the top. I personally use 1L/min for about 1.5 minutes using the big pore stone size (2 micron) on a wand. So it's at the bottom of about 12 gallons. Never grabbed a do reading though.

 

[DurtyChemist]

I have no idea what my regulator flows. I bought it used in the classifieds on this website. I open it the entire way and turn it off after 1 minute and let the remaining oxygen in the line run out before removing it. I just checked a freshly pitched batch of 1.047 wort and it's fermented in 72 hours. It's probably the fastest I've had an ale ferment.

EDIT: I believe the max my regulator can go (no gauge to verify) is 100 psi and 180 CFH according to some comparable units I find online. I'd be injecting 3 cubic feet into wort each minute. Since you're using a medical unit I'm confident you can find the oxygen flow rate for each setting. I recall from being a lifeguard there is a limit for what a person needs or what you need more training for. I think it was around setting 4 or 7.

 

[day_trippr]

fwiw, in Yeast, Chris White seemed to favor 1 LPM for 2 minutes through a .5u stone for a 5 gallon batch.
I changed that up a bit and run .5 LPM for 4 minutes through a .5u stone...

Cheers!

 

[mito]

I tried to put down some information i found across the internet and make a calculator. It is based in a lot of assumptions but the result somehow seems logical to me.
Maybe its worth a try and i could use some feedback too.
https://we.tl/RFb8aPpDJP

 

[wapitiscat]

This Mr. Wizard article in BYO goes into some of the chemistry of wort aeration. It made sense to me and I use his math to guide my wort aeration. Same setup as IslandLizard.

Todd

 

[IslandLizard]

I tried to put down some information i found across the internet and make a calculator. It is based in a lot of assumptions but the result somehow seems logical to me.
Maybe its worth a try and i could use some feedback too.
https://we.tl/RFb8aPpDJP

Looks interesting. If the formulas are correct it can help calculate dissolved O2 in a wort with a certain SG. Vessel geometry and height play a role as well, don't you think?

I use 6.5 gallon (25 l) fermentation buckets with 5.5 (21 l) gallons of wort. I run O2 through a 0.5 micron stone on a wand at the bottom at a rate of 1/4 liter per minute for 4-8 minutes.* Any higher flow rate and I see lots of surface rippling, which is O2 escaping that didn't get dissolved. At the 1/4 liter rate I get some rippling but also a lot of foaming, which I guess is good.

A tall narrow vessel would give higher efficiency. Or even better yet, inject into the wort stream on her way to the fermentor.

Without Google translate it's all Greek to me.

* I previously mentioned running O2 at 1/2 l/m for 2 minutes. I've gone to using lower flow rates trying to get more O2 into the wort, while there's less escaping from the surface (rippling). My flow meter goes down to 1/32 l/m, but it would take an extraordinary long time to get to 10 ppm O2 that way.

 

[mito]

Without Google translate it's all Greek to me.
.

This probably fixes that

https://we.tl/869OERCBpQ

Regarding the geometry, yes, i do believe it plays its role as well as the diffuser size.
But as long as you dont see bubbles coming out of your beer you can assume 100% solubility despite vessel geometry etc. Otherwise its a guess how much oxygen is dissolved or a trial and error if you have a DO meter.
Fine stones and narrow vessels are actually make the bubble easier to dissolve by making it smaller and keeping it in more time in wort. Flow rate on the other hand only concerns the application time. Actually with more time you are compensating the loss on the surface. This is what i try to cover by a solubility percentage. In fact BYO says that an 100% solubility isnt a bad assumption but i don't believe that's the case.

I am guessing a 70% because seeing bubbles its cool and provides a good visualization (aah and there nothing better i can do with my gear ) but a 50% wouldn't be too small either.

Inline injection is a different thing. Oxygen cant escape easily and flow rate of oxygen needs to respect the flow rate of the wort.

I have heard everything from half to 10 minutes but the problem is that without a meter is difficult to know if you under or over aerating.

 

[IslandLizard]

Thanks for the update! Much clearer now.

Even at 1/4 l/m I see some rippling (and foam). It makes me wonder where the rule to oxygenate for 1 minute at 1 l/m came from. Obviously oxygenation efficiency at that pace is far from ideal with small 5-10 gallon batches in small, relatively shallow fermentors. I have the feeling only 1/4 of that gets dissolved, if that, which means one would need to apply for a longer time, wasting even more gas at that rate.

I don't need visualization at the top of the wort/beer. I see the stone foaming when I pull it up, that's enough feedback for me. Seeing rippling and bubbles doesn't excite me, instead it makes me wonder how much O2 didn't make it into the wort.

BTW, I oxygenate for 1 minute, then pitch the yeast, stir and continue oxygenation for 4-8 minutes ay 1/4 l/m. I believe stirring may remove some of that dissolved O2 out of solution, so all that hard work goes partially out the top.

Inline injection is another can of worms. Not worth the effort for small homebrew sized batches, if there are decent (but not perfect) alternatives. Just getting the wort flow to be stable is a major task. Plus more equipment to clean and sanitize.

 

[IslandLizard]

I have no idea what my regulator flows. I bought it used in the classifieds on this website. I open it the entire way and turn it off after 1 minute and let the remaining oxygen in the line run out before removing it. I just checked a freshly pitched batch of 1.047 wort and it's fermented in 72 hours. It's probably the fastest I've had an ale ferment.

EDIT: I believe the max my regulator can go (no gauge to verify) is 100 psi and 180 CFH according to some comparable units I find online. I'd be injecting 3 cubic feet into wort each minute. Since you're using a medical unit I'm confident you can find the oxygen flow rate for each setting. I recall from being a lifeguard there is a limit for what a person needs or what you need more training for. I think it was around setting 4 or 7.

I think you've got the wrong regulator, or reading something incorrectly.

3 cu ft/min (?) is an astonishing flow rate! My tank is 40 cf, at that rate it wouldn't last even 14 five gallon batches, less than a year for me. At 1/4 l/m for 10 minutes I'd use 2.5 liter of O2. Say 3 liters, with purging/cleaning. At that rate, the 40 cf tank will last 28x40=1120 batches. At 20-25 batches per year, I won't live long enough to use it up.

 

[mongoose33]

How is everyone determining flow rate? I have a regulator w/ a valve on it but no gauge nor any way to determine how many liters/minute are flowing.

I have bubbles making it to the surface, as I have no reason to think I'm getting less dissolved O2 just because it's not all dissolving. I also figure I'm creating an oxygen-rich headspace in the fermenter and some of that will dissolve back into the wort. How much, same problem as liters per minute. No way to know.

 

[IslandLizard]

How is everyone determining flow rate? I have a regulator w/ a valve on it but no gauge nor any way to determine how many liters/minute are flowing.

I have bubbles making it to the surface, as I have no reason to think I'm getting less dissolved O2 just because it's not all dissolving. I also figure I'm creating an oxygen-rich headspace in the fermenter and some of that will dissolve back into the wort. How much, same problem as liters per minute. No way to know.

Are you using the disposable red O2 tanks from the hardware store? Those regulators don't have an adjustable flow rate. I would turn it open just enough to see some thick foaming develop around the stone when first immersed, then pulled out a Starsan container, or your wort/beer.

Note, with those tanks, close the valve all the way after use. They are notoriously slow leakers. Someone here claimed to get 20+ batches out of that small tank, which seems about right.

Shamelessly copied from here:
Bernzomatic = 1.4 oz. of O2 = 40 grams = 1.25 moles O2 (40 g/32g/mole of O2) = 28 liters of O2 at STP (1 mole of a gas is 22.4 liters at STP - standard temp & pressure)

28 liters of O2 dispensed at 1/4 liter for 4 minutes (1 liter) per batch is 28 batches! At twice the usage per batch, 14 batches. Use frugally at slow flow rates.

My regulator/flow meter looks similar to the one in the OP's picture, except it's green and goes all the way down to 1/32 l/m.

As with CO2, there is no O2 blanket covering your wort/beer after applying O2. It may be a bit richer in O2 for a short while, especially in a narrow carboy neck, but will equalize soon with the atmosphere. In an open bucket, it flows right out. Unless you oxygenate under pressure (e.g., in a keg) there's no way to get that O2 that bubbled out, back in there.

 

[mongoose33]

Are you using the disposable red O2 tanks from the hardware store? Those regulators don't have an adjustable flow rate. I would turn it open just enough to see some thick foaming develop around the stone when first immersed, then pulled out a Starsan container, or your wort/beer.

Note, with those tanks, close the valve all the way after use. They are notoriously slow leakers. Someone here claimed to get 20+ batches out of that small tank, which seems about right.

Yes, I use those red tanks, and the brass-colored valve. It does allow me to regulate the amount of O2, but there's no gauge or anything else to determine flow rate.

I haven't had too much trouble w/ it, and no leaks. But I keep a spare tank just in case.

 

[IslandLizard]

Yes, I use those red tanks, and the brass-colored valve. It does allow me to regulate the amount of O2, but there's no gauge or anything else to determine flow rate.

I haven't had too much trouble w/ it, and no leaks. But I keep a spare tank just in case.

If you see large bubbles escaping to the surface, that's O2 that didn't make it into your beer, so turn it down. A little rippling is probably inevitable. Ideally none should reach the surface.

You could measure the flow rate with an inverted graduate or marked beaker in a bucket of water or Starsan, and make corresponding markings on the regulator valve. At least you get some idea what you're supplying.

I'd go for 1/4 liter/minute for 4-8 minutes depending on your gravity and yeast.

 

[mongoose33]

Yeah, I'm probably wasting some of it, but I figure that too much is better than too little. This last time I did it (S-05) that yeast lagged for about 21 hours, and then it took off. That was Saturday at about 1:30pm; today is Wednesday after midnight, and it's STILL going strong. Huge krausen and it's just perking away. I mashed it at lower temps (about 151) than I usually do, hoping for more attenuation. Well, the way this thing is going, I suspect I'm getting that.

I've never had active fermentation for this long before; ferm temp is 64 degrees, maybe that's why, instead of the usually higher temps at 68 or so.

 

[IslandLizard]

Yeah, I'm probably wasting some of it, but I figure that too much is better than too little. This last time I did it (S-05) that yeast lagged for about 21 hours, and then it took off. That was Saturday at about 1:30pm; today is Wednesday after midnight, and it's STILL going strong. Huge krausen and it's just perking away. I mashed it at lower temps (about 151) than I usually do, hoping for more attenuation. Well, the way this thing is going, I suspect I'm getting that.

I've never had active fermentation for this long before; ferm temp is 64 degrees, maybe that's why, instead of the usually higher temps at 68 or so.

More O2 in the solution is better (although there's a limit to usefulness) but running it faster doesn't mean more gets dissolved. Running longer at slower rates gives it more opportunity to dissolve, IMO.

Well sure, lower temps slow the growth/lag phase down.

My Belgian IPA at 1.074 was bubbling away happily within 8 hours at 65F => 68F. I used a large fresh starter of WY3522.

Last night it was down to 1.024 already after 48 hours! A little faster than I had anticipated, I wanted to ramp up the temps a bit more around 50% attenuation. The sample tasted awesome! I then added homemade candi syrup dissolved in some extra wort I had saved out, about 3 quarts in total. Chugging away at 75F now.

 

[TLaffey]

How is everyone determining flow rate? I have a regulator w/ a valve on it but no gauge nor any way to determine how many liters/minute are flowing.

I'm using one of these: https://www.amazon.com/gp/product/B01LZ8I17N/?tag=skimlinks_replacement-20 "LZQ-2 0-3LPM 93mm Acrylic Gas Air Oxygen Flow Meter"

 

[Jwin]

FYI, blichmann is now has nearly the same o2 regulatorss OP for sale for $45+.
I got one identical, except green, off of eBay for $9.34. brand was Puritan Bennett. Works great for the 6 minutes a month that I need it to.
I know this is off topic and a bit of a necro, but it needs to be put out there.

 

[duelerx]

I tried to put down some information i found across the internet and make a calculator. It is based in a lot of assumptions but the result somehow seems logical to me.
Maybe its worth a try and i could use some feedback too.
https://we.tl/RFb8aPpDJP

Seems the link stopped working, do you still have your file available?