O2 Results from my new O2 meter!

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Demus said:
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
 
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.
 
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.
 
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.
 
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.
 
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??
 
[...]
* 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!
 
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.
 
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.
 
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!
 
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!!
 
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!!!
 
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.
 
* 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.
 
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.
 
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.
 
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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.
 
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!! :mug:
 
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.
I haven't figured out what they use in the small medical 'flow meters'. I'm guessing either a needle valve with preset detents (like used with a Thorpe tube, but set at the factory), or a fixed orifice with a variable backpressure. Either way, or even if it's a different way, I doubt the ~2psi downstream backpressure affects the rate much, since the upstream pressure is likely 60psi or greater. I can't see them getting accurate/precise single digit psi changes with a diaphragm that small. That said, the Thorpe tubes are a much more accurate meter when dealing with variable downstream pressures. If someone combines a Thorpe tube flow meter with one of the cheap medial flow meters with/without a stone attached, we would know for sure how much downstream backpressure affects them.

One thing about injecting the O2- the bulk of the diffusion happens at the surface (provided the flow is high enough). From memory, it is ~90% compared to the diffusion that occurs as the bubbles rise. There are limits and variables, of course, but the basic guidelines are to have a moderate patch of bubbles breaking the surface. As long as the currents aren't so violent as to collapse the bubbles in the stream (as mentioned earlier), but enough to cause some turnover, the premise holds.

I would have to search for the paper, but it was an involved study related to aerating settling ponds (yes, ponds of poo). The critical factor was the 'skin effect' as the bubbles popped on the surface. Smaller bubbles were still better than larger ones.
 
thanks CWI. after thinking about your assessment of med cylinders and the backpressure being overwhelmed, i'm inclined to agree with you.

very interesting about the O2 bubble physics. there's alot about gas/liquid interfaces that's counterintuitive. if you ever dig up that paper, please fwd.
 
This is a great thread full of excellent info.

Thought you might be interested in this calculation: If you dissolve all of the oxygen from one pint of air at STP into 5 gallons of wort the O2 concentration will be 8 ppm. I did the calculation because I was wondering if there was really a significant amount of oxygen in the small headspace of a full carboy. Of course you can't get 100% of the oxygen to go into solution, but it gives you a starting place for a thought experiment. If you purge the headspace with pure O2, seal it up with a solid stopper, and wait long enough the concentration will be well over the required 8 ppm. Shaking with a pure oxygen headspace would get you there a lot faster.

I have an oxygen system, but haven't used it yet. My best fermentations so far have been aerated by draining cooled wort slowly into the carboy while rocking it continously. Shaking the full carboy is too hard to do effectively, but when it is only 1/3 full you can really get some foam going. I spend about 10 minutes transfering/shaking and the wort has about 4 inches of foam on it when I'm done. You can get a violent sloshing action going in a partally filled carboy when the you get the rhythm right and it only takes a tiny rocking motion.

On the other hand, if shooting in a little oxygen means that I don't need to make a starter then it is a big time saver. Can't wait to try it.
 
On the other hand, if shooting in a little oxygen means that I don't need to make a starter then it is a big time saver.

It doesn't mean that you don't need to make a starter. You should still observe proper pitching rates.
 
I show a picture of the setup I use here:

https://www.homebrewtalk.com/f11/o2-flow-meter-216614/#post4440476

Without a true flow meter, I think your data will be too noisy. I'm thinking about getting an O2 meter too and would like to figure out a Mr Malty type calculator that would let you plug in the Volume of Wort, Gravity, Temperature, desired ppm and flow rate and it would tell you how long to Oxygenate.

To the OP, do you still like the meter you have? Would you recommend it?
 
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