O2 Results from my new O2 meter!

[Huff360]

I have a medical oxygen regulator, something like this:

http://www.ebay.com/itm/H-M-Medical...ltDomain_0&hash=item2303d153a7#ht_1290wt_1152

I set it to 0.5 Lpm. Works great

Say...nice find! Will this fit on one of those red cylinders typically found at home depot or lowes? Thanks for this link! Just what I needed!

No, it will not. The one linked to above uses a CGA-540 fitting. That is what a "welding bottle" uses. You can usually get a small tank full of O2 from AirGas or somewhere like that for about $75 or so. It will last you forever compared to the Red Burnz-o-matic tanks.


Medical oxygen tanks use a CGA-870 valve and usually require you to have a prescription to fill. Sometimes you can buy a cheap medical tank on craigslist and swap it for a welding tank at AirGas. I would call and ask them if they would do that first. You don't want to get stuck with a $30 medical tank that you can't get filled.

 

[dstar26t]

I played around with an O2 meter a couple years ago and recorded this data:



The measurements shown on that table were the only ones I got from that meter before it wouldn't calibrate anymore. I was pretty disappointed with it. It is the older Milwaukee model that the MW600 replaced. Make sure to calibrate yours often to make sure it's working properly.

 

[itzkramer]

I would also like to see readings for the following:

Shaking with the headspace filled with pure oxygen.

Pouring back and forth between 2 buckets.

The siphon sprayer nozzle from Midwest.

Thanks for taking the time to run your tests and posting the results. Greatly appreciated.

 

[jtejedor]

I played around with an O2 meter a couple years ago and recorded this data:



The measurements shown on that table were the only ones I got from that meter before it wouldn't calibrate anymore. I was pretty disappointed with it. It is the older Milwaukee model that the MW600 replaced. Make sure to calibrate yours often to make sure it's working properly.

Man those numbers are all over the place.

 

[dstar26t]

I forgot to explain that this chart is for 5.25-5.5 gal batches in a 6.5 gallon carboy oxygenated with a .5 micron stone. They are listed chronologically, not by OG or temp or time so you have to study the data for a few minutes. There are too many dependents to graph it out. The last 6 rows of data were for 2 beers with 3 readings taken on each after additional oxygenation.

 

[aarong]

Very interesting thread thanks for the info.

 

[jtejedor]

So I guess 75 seconds is the sweet spot then? From dstars chart it appears thicker worts need up to 90 seconds or longer. Good info I usually go 60 seconds because that is the info that came with my kit but I have had it for like 4 or 5 years maybe that is old info. 60 seconds seems to work.

 

[Gavagai]

Any idea what 1 L/min or 3 L/min looks like?

 

[Rundownhouse]

I've posted before about testing wort with a DO meter. My SOP is to give ales 60s full throttle flow with one of the disposable tank/regulator setups, big ales/lagers 90s, and big lagers 120s. If I remember right, I got a PPM of ~15 on a BoPils at about 50F after 120s, and something like 12ppm on an ale at 60s.

One thing to keep in mind is that the meters vary wildly on how reliable they are at reading different things. Some meters don't do well with oxygenated wort but are great with finished beer, some can do both gas and liquid, etc. Knowing your DO meter comes with everyday use-type experience that's just really hard to get outside of a professional brewing setting.

I'm... skeptical... of something reading 300ppm. Maybe dstar meant ppb?

 

[Demus]

I would also like to see readings for the following:

Shaking with the headspace filled with pure oxygen.

Pouring back and forth between 2 buckets.

The siphon sprayer nozzle from Midwest.

Thanks for taking the time to run your tests and posting the results. Greatly appreciated.

I'd like to see these too. I did read in "Yeast" that air only has 8 ppm or so, making it impossible to get more than 8 with any non-O2 method. Being involved in both aviation and scuba diving, I understand a bit about how gasses diffuse into liquids. Basically the bigger the differential (called partial pressure) the faster the rate of diffusion. So if you target is 8-12 ppm, you can only get to the minimum of your target and it will take a LONG time to get there because of the low partial pressure. This fits with test I read done by White Labs that found 5 minutes of "vigorous" shaking only resulted in 2.7 ppm dissolved oxygen. I believe this is one of the biggest causes of problem fermentations among newer brewers.

 

[dstar26t]

I'm... skeptical... of something reading 300ppm. Maybe dstar meant ppb?

That's calculated ppm at 100% efficiency, only 5.8% of it was dissolved so there was 17.5 ppm in solution measured.

 

[passedpawn]

Great thread guys. Love it.

 

[aarong]

I'd like to see these too. I did read in "Yeast" that air only has 8 ppm or so, making it impossible to get more than 8 with any non-O2 method. Being involved in both aviation and scuba diving, I understand a bit about how gasses diffuse into liquids. Basically the bigger the differential (called partial pressure) the faster the rate of diffusion. So if you target is 8-12 ppm, you can only get to the minimum of your target and it will take a LONG time to get there because of the low partial pressure. This fits with test I read done by White Labs that found 5 minutes of "vigorous" shaking only resulted in 2.7 ppm dissolved oxygen. I believe this is one of the biggest causes of problem fermentations among newer brewers.

I have been searching for where it says that you only get 2.7 ppm from vigorous shaking. I did try wyeast website. I am very curious about this. Do you still have a link for this info? Thanks!

Also I heard from white labs that you can get 8 ppm from vigorous shaking (but I doubt it) unless you can pick up the whole bucket and shake the crap out of it.

Thanks

 

[lockwom]

Another test that you might consider would be to skip using the wand and instead flood the head space of the fermentor with O2 for a few seconds then shake the fermentor for 30-seconds. Do this flood and shake process a total of two times then measure the results. I read elsewhere recently that this is another good way to oxygenate wort with pure O2 without the wand. I'm curious what level of dissolved O2 this method would achieve.

Thanks for posting your results!

I don't have a DO meter, but I've saved substantial O2 using this method. I purge the headspace a few seconds until I can smell wort aroma escaping, cap tightly with foil and vigorously tilt the carboy back and forth on the floor to absorb. Not too much effort, and I repeat two to three times, depending on OG.

Not certain if I hit the ideal O2 range, but equivalent recipes perform as well as the O2 stone with less oxygen, and less sanitation risk.

As dstar26's data indicates, a lot of O2 escapes with the stone. I feel the headspace purge/shake can get you in range with less oxygen.

 

[BrewingPrepper]

I would be interested in seeing what the spray aerator can do. My LHBS says that is what he uses and sells with his kits. I have used it for both my brews. However I really want to get more oxygen in I think it has to do with my weak fermentation.

 

[Huff360]

I would be interested in seeing what the spray aerator can do. My LHBS says that is what he uses and sells with his kits. I have used it for both my brews. However I really want to get more oxygen in I think it has to do with my weak fermentation.

You are bound to the same upper limit as any other method of aerating. There is only so much oxygen in air. The only way you can get over 8ppm is with oxygenation of some manner.

People have brewed great beer for many many years without using pressurized Oxygen. Spalsh/shake vigorously, follow proper pitching guidelines, and use a yeast nutrient and you should have good fermentation.

Pressurized Oxygen, like water chemistry, should be something you worry with after your beer has gotten as good as it possibly can. Superior sanitation, ferm temp, full boil, and pitch rate should all be figured out first. In my opinion, in that order. If you have only made 2 batches, there are likely a lot better places for you to spend your money and make glarger improvements on your beer.

 

[zymurgistic]

gavagai,
you're basically asking the central question, how to judge volumetric flowrates. unfortunately, there are too many moving parts to be able to even qualitatively say what 1 lpm vs 3 lpm looks like, in terms of bubbles formed, foam formed on top, etc. the only way to be sure is to pick up a flowmeter. i got a cheap plastic one from welder supply for about $15 that i plan to install inline for next test. then there's the whole question about how much gas actually dissolved instead of bubbled to surface and escaped. if you're ready to invest in O2 tank, i'd say figure out who can loan you a DO meter for a wkend and then, using buckets of water and plain sugar to certain gravs, fix on a good combo of flowrate/psi/time that gives you over ten ppm and then you can just use that forevermore with confidence.

 

[zymurgistic]

so if anybody out there has a DO meter, a flowmeter*, and lots of time and a fresh 20cf tank fill of O2 to burn, here are the tests we'd all like to see.

--2 micron vs. 0.5 micron diffusion stone
--DO rates at different OG's
--time versus flowrate combinations, which is most efficient? assuming that slower rate for longer time results in less loss of O2 bubbling off at surface, what is the diminishing returns point? is it linear, or is there a sharp ramp off somewhere?

if you picked up half a dozen cheapo 5-gal buckets from Lowes/HD, and a giant bag of table sugar, you could simulate worts for testing. if you wanted to test three different gravities (1.050, 1.065, and 10.80), and three different flowrate/time combos, AND the two different airstones, this would take

2 airstone x 3 gravs x 3 flowrate/time = 18 tests.

* using a medical oxygen regulator with the lpm setting won't work as a flowmeter here, unfortunately. that's only accurate for unrestricted flow, and we have restricted flow due to the airstone, and to a lesser extent, the atmospheric pressure of 15 in or so of liquid above the outflow. so it has to either be a thorpe tube style volumetric flowmeter inline from the tank, or just regulator psi. reg psi will be a decent number since, if another guy is using the same micron airstone, his rig should act more or less the same as yours, and same psi/time should give same ppm DO. the advantage of the thorpe tube is that it will also tell you how much of your tank you're using per bucket, which is also a concern.

any takers??

 

[day_trippr]

[...]
* using a medical oxygen regulator with the lpm setting won't work as a flowmeter here, unfortunately. that's only accurate for unrestricted flow[...]

I disagree with your presumption wrt restriction in the system giving inaccurate flow meter readings. An analogy would be a household water meter not working unless all of the taps were wide open...

Cheers!

 

[TTB]

I have been searching for where it says that you only get 2.7 ppm from vigorous shaking. I did try wyeast website. I am very curious about this. Do you still have a link for this info? Thanks!

Also I heard from white labs that you can get 8 ppm from vigorous shaking (but I doubt it) unless you can pick up the whole bucket and shake the crap out of it.

Thanks

The book "Yeast" by Jamil and Chris White. Shows a table of oxygen levels by various methods. IIRC, shaking ranged from 2.5-4.5.

I think it may have said a ridiculous amount shaking could get you to 8...but I don't think most people (even if you think you are shaking a lot) can get that from shaking.

 

[zymurgistic]

daytrippr,
i think you misunderstood. i was referring to the medical oxy regulators which have a selector switch for Liters/Min. these regulators do not actually have a volumetric flowmeter in them, they have simply been calibrated to select a certain psi which, during their normal usage of unrestricted flow of gas out the feed tube, will result in the selected lpm shown on the selector knob.

you are correct that a household water meter IS a volumetric flowmeter, and DOES gives accurate volumetric reading of fluid passing thru pipe regardless of flowrate. i was simply pointing out that the medical oxygen regulator lpm selector switch does not work this way and so don't make the mistake of thinking that you can use that to measure lpm in our homebrewing application. that's why i suggested the use of an inexpensive thorpe tube inline from O2 tank to directly measure volumetric flowrate.

 

[day_trippr]

Ah, ok, my bad, I've never seen such a regulator, and when I see "flow meter" I've always assumed a flow gauge is present (I don't think I'd trust any regulator that didn't have a meter or gauge of some appropriate type).

All of the flow meters I have (for welding as well as my beer oxygenation rig) have integrated flow gauges...

Cheers!

 

[zymurgistic]

CORRECTION: i just noticed that i had read my new gauge wrong. it wasn't 13.5 psi, it was 13.5 kPa, which is 1.958 psi. sorry everybody! so it was 3 min @ 2 psi/13.5 kPa thru a 2 micron diffusion stone into a five gallon bucket at 68 degrees F that gave me my 12 ppm DO. hopefully everyone will see this correction!!

 

[Demus]

All calibrated scientific measurement aside, I've been using one second per point of gravity for 5 gallon batches with great success. 1.045, 45 seconds, 1.060 gets a minute, etc. My flow is enough to agitate the surface without excessive foaming. I suspect the flow rate is a factor, but maybe not as much as we think. As you push the flow up, you get bigger bubbles that shoot to the surface faster, which wouldn't add more oxygen than slower, finer bubbles. Again, I haven't measured this and am not claiming it as fact, but it makes sense and I've had very consistent results. I don't send my starters off to a lab to have the cells counted either but that's working well too!!!

 

[zymurgistic]

i like the time unit-per-point of grav idea. hadn't thought of that. as long as you're seeing vigorous ferments and good attenuation, it's all good. and i suspect you're right about smaller bubbles being more efficient. makes sense.

 

[Huff360]

* using a medical oxygen regulator with the lpm setting won't work as a flowmeter here, unfortunately. that's only accurate for unrestricted flow, and we have restricted flow due to the airstone, and to a lesser extent, the atmospheric pressure of 15 in or so of liquid above the outflow. so it has to either be a thorpe tube style volumetric flowmeter inline from the tank, or just regulator psi. reg psi will be a decent number since, if another guy is using the same micron airstone, his rig should act more or less the same as yours, and same psi/time should give same ppm DO. the advantage of the thorpe tube is that it will also tell you how much of your tank you're using per bucket, which is also a concern.

Hmmmm - I'm not 100% sure on this caveat. Most all of the medical regulators will deliver the set flow up to 50 psi.

I haven't put a pressure gauge on my system, but I doubt that it is above 50 with the .5 micron stone. I just slip fit the hoses on my system and they don't blow off.

 

[zrule]

Wow....all great infomation as I have just started using a stone with the hardware store O2 bottles. Now I have a starting point and I will use the sec/per point of gravity method. Prior to that I used a drill and paint stirrer for around 60 sec and had good results. I just want to try something better.

Thanks for the useful info.

 

[nsrooen]

From the research I have done and have been using.

.5 micron stone for pure oxygen. Smaller bubbles dissolve easier in your wort. You do not want the oxygen bubble to reach the top of your wort. You want them to dissipate within the wort before they reach the top.

I do 1 ppm for 1 minute per the Yeast book recommendation by Chris White. Not sure what the optimal setting would be for a 2 micron stone.

Oxygen Welding Tank -
http://www.harborfreight.com/20-cubic-ft-oxygen-cylinder-92810.html
Get an empty from Harbor Freight with 20% off coupon and exchange it at a gas supply place for a full one. Supposedly medical tanks and welding tanks are filled exactly the same way from the same source, one is just is "certified". Bigger upfront investment but you wont have to constantly mess with getting the small ones at the home improvement stores, The 20 cubic tank will last you a long, long time.

Add this -
http://www.amazon.com/dp/B00697ZYTA/?tag=skimlinks_replacement-20
Whatever you get needs a CGA450 connection for the tank. It is great to be able to precisely control the flow of oxygen.

and a stainless steel oxygen wand and you are set. The wand allows you to quickly / easily position the stone at the bottom of your fermenter.

I did a fair amount of research before I decided on this route and so far I have had excellent results.

 

[fxdude]

Great info here, I started adding pure O2 to my wort before I even started doing yeast starters and saw great improvements in my fermentation.

 

[Demus]

Great info here, I started adding pure O2 to my wort before I even started doing yeast starters and saw great improvements in my fermentation.

I did too. I think that's why I got away without doing starters on so many batches. I honestly believe for brews under 1.060 OG it's actually more important than a starter, assuming fresh quality yeast. That said, you add in the starter to your process and your chances of a bad batch go down even more. I think that's what home-brewing is all about. We can never be perfect or as precise as we'd like, but with knowledge and simple at home techniques we can make some damn fine beer!!