Some Oxygenation info from Wyeast - Home Brew Forums

 Home Brew Forums > Some Oxygenation info from Wyeast

04-09-2008, 04:35 PM   #1
mr x
Recipes

May 2007
Mainly Halifax
Posts: 1,576
Liked 4 Times on 4 Posts

I had e-mailed Wyeast regarding this oxygenation theory. Some people may find this info useful:

I am about to get an O2 aeration system and have a couple of questions.
When you figure 1 min of O2 into 5 gallons will give 12ppm, is that from
a wort at 0ppm, or does that include a base level in the wort of maybe 4
ppm from splashing into a carboy?

Can you estimate the absorption rate of the O2 into the wort? I did some
math to come up with these numbers:

12ppm(or mg/L) of O2 into 20L of wort requires 240 mg of O2.

Converting this to moles O2 (32 g/mole) I get .0075 moles O2.

Using an ideal gas law assumption (22.4 liters/mole), I get a required
volume of pure O2 of .168L - or 0.0059 Cubic feet. required for 12 ppm.

To inject the O2 for 1 minute through a stone, I would think you must be
using very low pressure, or a lot of O2 is lost. Is that correct?
-------------------------------------------------------------------------------------------------------------
Thank you for the email.

The oxygenation time is based on starting with <1ppm DO.

I do not have an absorption rate for O2 into wort as there are many
variables involved including stone surface area, pore size, wort volume,
wort temperature, wort gravity, and pressure. The largest problem (in
my opinion) with efficiently dissolving oxygen into wort is the surface
area of the stone with respect to the volume of wort. The optimal
method for dissolving O2 in to wort is to pass the wort stream past a
stone in line, post heat exchanger, similar to most commercial
breweries. This insures a high ratio of stone surface area to wort
volume.

To finally answer you question, a lot of O2 is lost.

I have been using a different method of injecting O2 into the headspace
and then shaking the carboy for 30 seconds. I am achieving good DO
levels (approx 12ppm) when doing this twice.

I hope that this helps.
__________________
This place really went to hell. Follow the OF standard stout. Bye.

07-01-2008, 06:25 PM   #2
Alamo_Beer

Recipes

Aug 2006
Manor, Tx
Posts: 2,439
Liked 9 Times on 6 Posts

Wow thats cool......it's awesome when you get a REAL email back not just a "thank you for you question"

I wonder why the guy likes his method of 02 AND shaking instead of JUST 02??

07-01-2008, 06:30 PM   #3
FlyGuy

Recipes

Jan 2007
Calgary, Alberta
Posts: 3,605
Liked 183 Times on 53 Posts

Good post -- thanks for sharing that email.

Quote:
 Originally Posted by Alamo_Beer I wonder why the guy likes his method of 02 AND shaking instead of JUST 02??
I bet it is because it eliminates the need for a diffusion stone. Just inject through tubing into the headspace (say, though a carboy cap), then shake it in. I use the hybrid method -- inject through stone while gently shaking.