All You Ever Wanted to Know About Oxygenation - Page 3 - Home Brew Forums

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07-25-2013, 04:49 PM   #21
nhwrecker
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Interesting post. Where does that equation come from, and how would using a 2 micron sintered stone (instead of 0.5 micron) change the constant? If it's a function of the volume, then a factor of 4 change in the diameter would equate to a difference of 64?
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07-25-2013, 06:16 PM   #22
pmcint01
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Anyone know what it costs to fill the 20 CF welding type O2 tanks?

07-25-2013, 07:51 PM   #23
drunkenmonk

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Quote:
 Originally Posted by nhwrecker Interesting post. Where does that equation come from, and how would using a 2 micron sintered stone (instead of 0.5 micron) change the constant? If it's a function of the volume, then a factor of 4 change in the diameter would equate to a difference of 64?
That's a good question. It's different than force carbonation where you've got a sealed vessel and you're interested in dissolving volumes of C02. It's a function of the size of the oxygen bubbles and how readily they dissolve into the wort. As an extreme example, just putting a hose into the wort and turning the oxygen on wouldn't oxygenate the wort very well as bubbles would come out of the hose, bubble to the surface of the wort, and dissipate into the head space (and no pressure build up like force carbonation since the fermenter is not a sealed container).

0.5 micron is better than 2 micron, I just don't know how much. My equation was based on empirical data where they measured how much volume of oxygen it took saturate the wort with oxygen using a dissolved oxygen meter. You could do the same test with a 0.5 micron stone ... or someone more motivated/smarter than I could analytically derive the result based on solubility.

07-25-2013, 07:52 PM   #24
drunkenmonk

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Quote:
 Originally Posted by pmcint01 Anyone know what it costs to fill the 20 CF welding type O2 tanks?
\$20 or less and it's going to take you a long time to deplete a 20 CF 02 tank; especially compared to how long it would take a typical homebrewer to deplete their CO2 tank.

07-25-2013, 07:54 PM   #25
TrickyDick

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Do you recall if the references you consulted discussed wort temperature? I know that many gasses have dramatically different solubility at varying temps, notably co2. Though I do not know if oxygen, being a smaller molecule than co2, like nitrogen, is less soluable than co2 at comparable temperature differences.

TD

07-26-2013, 05:23 AM   #26
drunkenmonk

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Quote:
 Originally Posted by TrickyDick Do you recall if the references you consulted discussed wort temperature? I know that many gasses have dramatically different solubility at varying temps, notably co2. Though I do not know if oxygen, being a smaller molecule than co2, like nitrogen, is less soluable than co2 at comparable temperature differences. TD
No specific reference. I assume around 70F.

08-27-2013, 01:09 AM   #27
erikrocks

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Any idea how the formula would look if I'm using a .5 micron stone?

08-27-2013, 01:22 PM   #28
drunkenmonk

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Quote:
 Originally Posted by erikrocks Any idea how the formula would look if I'm using a .5 micron stone?
Time to reach target levels of oxygen would be faster, but not sure how much faster. Results for 2 micron stone were derived empirically.

08-27-2013, 08:49 PM   #29
ArcLight
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The problem with a 0.5 micron stone compared to a 2 micron stone is it's easier for it to block up. And harder to un block.

The other thing people who use Oxygen need to realize is a lot of the O2 is not staying dissolved in the wort, it gradually bubbles to the surface. Now it may later be reabsorbed, maybe. Or maybe not.

So what I do is after adding Oxygen, I seal up the bucket, and rock it back and forth for a while. This will help dissolve more O2.

What I'm curious about is what happens if you aerate with air by rocking for a minute, then add Oxygen, and rock some more. Does aerating with air make it harder for additional O2 to dissolve, and thus possibly counter productive?

08-28-2013, 12:36 AM   #30
TrickyDick

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I might see if this bears out with a DO meter test. Just picked one up. Also going with a new E type O2 tank and Pedi Regulator with my Williams Brewing SS wand and stone kit.
Hope this helps sort out stubborn lager fermentations for me.

TD