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O2 into H2O

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abyss

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I'm thinking of pressurising a corny full of water with O2 through the dip tube, let it sit overnight then
transfer it to my fermenter with my kit brew instead of using an oxy wand.
I can't see why it wouldn't work but am wondering how much pressure to use.
My other idea is to just connect a hose from the regulator to the fv tap and give it a gurgle.
 

Danscraftbeer

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I'd like to know what dissolved oxygen levels you get with different pressure. I charge my kegmenter with the new wort to up to 10 psi then roll shake it on the floor to dissolve the O2. It works very well. I don't know how accurate my gauge is though.
I read a comment somewhere on this forum from someone who had a DO meter and said that charging with 4psi and shaking well gets a DO level around 12. Temperature has an effect too.
 

abyss

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I'm thinking of starting at 10 psi. I'm not a scientist but.
 

Lyrebird_Cycles

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You can predict the [O2] vs pressure and temperature using Henry's law and the van 'tHoff equation.

The Henry's law constant for O2 in water is 3.2 x 10-2, the van 'tHoff coefficient is 1700K.

The Henry's law coefficient given is dimensionless, so Caq = Hcc x Cg where both concentraltions are in mol / litre.

Translating mol / litre O2 in gas to pressure for O2 assuming 22.4 litres / mole at STP and mole / litre O2 in solution to the more familiar mg/l [O2] at 32 g / mol gives a Henry's Law coefficient of 0.42 mg / l. kPa, note that this is absolute pressure so you'll need to add 101 kPa to your gauge pressure.

The above applies at 25 oC (298 K), let's assume you are doing this at around 4 oC (277K), the van 'tHoff equation is then

H(T) = Ho . e [coefficient. (1/T-1/To)]

with the coefficient already given as 1700, so the quotient is e [ 1700 . (1/277 - 1/298)]

= e 0.43

= 1.54

so at 4 degrees the Henry's Law coefficient will be 0.65 mg/l/kPa, again note this is absolute pressure not gauge.

10 PSI is about 70 kPa gauge or about 170 kPa absolute, equilibrium [O2] is therefore about 110 mg/l .
 

abyss

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Thanks LC I've just had a crack at it but my gauge is in litres per minute so I took it up to 20 l/m, burped it a few times and chucked into my lager fridge.
I'm brewing in the morning unless I go fishing and will let you guys know how it turns out.

image.jpg
 

SBOB

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Lyrebird_Cycles said:
You can predict the [O2] vs pressure and temperature using Henry's law and the van 'tHoff equation.

The Henry's law constant for O2 in water is 3.2 x 10-2, the van 'tHoff coefficient is 1700K.

The Henry's law coefficient given is dimensionless, so Caq = Hcc x Cg where both concentraltions are in mol / litre.

.
.
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10 PSI is about 70 kPa gauge or about 170 kPa absolute, equilibrium [O2] is therefore about 110 mg/l .
 

mstrelan

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But that's a direct quote from Jesse. It's a reaction to Walter.
 

Lyrebird_Cycles

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Ahh, OK; I haven't got to that episode yet.

I'm slow.
 

abyss

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I mixed my goo and oxy water up a couple of hours ago and already have some gurgling out of the air lock.
I used Morgan's Euro lager yeast 15g.
I'll keep yous posted.

image.jpg
 

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