confusion about gas for oxygenating

[omearabros]

Our local gas supplier is only able to supply "food grade" air and/or oxygen. Meaning, they make the gas by blending from liquid forms. This is known as "Aligal." I hear a lot of brewers calling their oxygen "medical grade" but the supplier says that only doctors can get that. So - is this "food grade" air suitable for oxygenating? The supplier claims that there would be no way for it to have contaminants because it's blended from pure forms. I'm still concerned.

He also supplies what's known as "breathable air" also supposedly contaminate free. I was also considering starting with air for various reasons. Is this "breathable air" suitable?

Bottom line - if the supplier says that "food grade" and "breathable" are contaminate free, should I trust him?

Cheers,
Tim

[Junkyard]

dont get breathable air, get pure oxygen.

Food grade should be fine, you can also go to a welding gas supplier and pick up welding oxygen. I was told by my local place that medical grade and welding grade oxygen are the exact same, come out of the exact same tank, except the medical grade is tested before being sent to a hospital, for QA sake.

[Hatchet Jack]

In many cases, you'll need pure oxy to get to the level of dissolved oxy that you want.


Aaron
Junkyard Brewing Co.
Moorhead M.N.

[gitchegumee]

I like air...

Not pure oxygen. Unless you're doing high gravity, there's no good reason to need pure oxygen IMHO. Pure oxygen is more often than not dosed too high resulting in over production of yeast and the production of useless yeast biomass instead of great beer. You would need a flowmeter calibrated for oxygen at the temperature and pressure that you inject at. Just blowing in pure oxygen without knowing how much you add is recipe for inconsistency. Contrarily, air will not oversaturate oxygen in your wort and you can use it without careful attention to any flowmeter. And it's cheaper to buy a small oil-less compressor than to buy gas. Some folks use air to "float" trub so it may be skimmed from the fermenter, or pumped into a drop tank for the same effect. Pure oxygen has been implicated in "burning" the wort as well, combining with wort constituents as opposed to just being dissolved. If you are using most dried yeasts, you will not need to aerate the wort. In any aeration situation, the gas should be food or breathable and sterile filtered before injection. This question would be best answered by your yeast supplier knowing wort style and gravity. Good luck!

[Hatchet Jack]

Wyeast disagrees with your theory, gitchegumee, but a brewer would need a D.O. meter to know for sure. Those are expensive.

http://www.wyeastlab.com/hb_oxygenation.cfm

Aaron
Junkyard Brewing Co.
Moorhead M.N.

[TL Services]

At ambient pressure & temperature, air will give around 8-9ppm of dissolved oxygen, assuming the wort of fully saturated with air. Cooling the wort will allow a greater level to be achieved as the only two factors controlling gas dissolution are Pressure and Temperature (it would be impractical to run a fermenter with a significant head pressure).

As has been mentioned, 8-9ppm of O2 should be fine, unless brewing at high gravity.

Over-oxygenating will, as gitchegumee has said, be very likely to result in yeast over-multiplication, leading to poor fermentation control and in the worst scenario, some unpleasant flavour defects.

Good oxygenation control - whether from air or pure oxygen - is vital in being able to assure consistent fermentation profiles and this needs either (a) a good, calibrated flow control or (b) a good dissolved oxygen meter...preferably both...to be sure of levels.

Hope that helps!

[omearabros]

Thanks for the info. I'm aware of the pros/cons of air vs. oxy and which I should use for what beer. What I'm wondering is about "breathable" and "food grade" and if those terms mean I can use those gasses without risk of contamination.

Thanks to everyone for their input. Am I good to go with "breathable air" and "food grade" oxygen?

[Junkyard]

pure oxygen regardless of what grade it is, is totally sanitary. Pure oxygen essentially burns, or oxidizes microorganisms, it'll even kill yeast upon direct contact. Thats another thing thats nice about oxygen: peace of mind. So yes, you will be fine using food grade pure oxygen.

As for breathable air, yes im sure you would be fine using this stuff too. But if you are going to be using air, i would just do as philip said and get a oil-less compressor and an inline filter. then you dont have to pay for it. cuz after all, its just air.

[gitchegumee]

You're right Aaron!

So Wyeast does disagree with me. I'm sticking my ground with air. I get 2 - 2 1/2 day fermentations from a fresh liquid pitch with great flavors and an appropriate amount of yeast growth. Air is pretty much foolproof. Oxygen is not. Unless you have the equipment to accurately measure flowrate of O2 at your temperature and pressure, then you have no control of oxygen content of the wort. For me, the (unsubstantiated) threat of lack of O2 vs. overoxygenating and overproduction of yeast and the potential of off-flavors is an easy choice. But this may only be my wort profile, my yeast choice, and my aeration techniques.

[Hatchet Jack]

We brew a lot of high gravity beers. So we use oxy. And Chris white from white labs echoes the same theory as Wyeast. He says you can get "satisfactory" results with air though. Never had a problem with too much yeast growth.


Aaron
Junkyard Brewing Co.
Moorhead M.N.

[gitchegumee]

Well that must be it...

My beers are relatively low OG @ 10.7-12.2P and ferment quite dry. Fermentation profile and flavors are spot-on. I have no reason to switch to pure oxygen, but certainly would if I was brewing high OG beers with a demanding yeast. Goes to show that different techniques are required for different beers!

[Natrat]

Medical grade oxygen=lowest grade (high dewpoint, 96% or better pure)
Aviation grade oxygen= low dewpoint, 96% or better pure
Welding grade oxygen=low dewpoint, 99.5% or better pure
Laboratory grade oxygen = lowest dewpoint, 99.995% or better pure

Any oxygen blended down from liquid oxygen will conform to welding grade, at least. I find best prices on aviation O2. Usually, unless they are blending from a nitrogen membrane system, suppliers will blend from their liquid bulk supply, and everything from welders grade down will be the same. Lab grade is pricey and way overkill for what we do.

FYI, the numbers come from the ASTM and NASA oxygen handler's handbook.

[Braxtol]

2 Words

Venturi Injector.

Sterile air from an air compressor through a hepacap filter.
Just as effective as pure O2 and 5000x less expensive.

[omearabros]

Great responses! Thanks so much everybody.

Cheers,
Tim

[Surf Money]

Great responses! Thanks so much everybody.

Cheers,
Tim

Hi Anyone have experience with a filter like this:

https://www.amazon.com/gp/product/B016XIWHGM/ref=ox_sc_sfl_title_1?ie=UTF8&psc=1&smid=A158LRHTFH4QLV

I am wondering if it removes microbiological impurities from air to allow oxygenating wort without risk of contamination?

Is there much risk of contamination if i use this type of filter and an oil less air compressor?

Cheers