Co2 in keg transfer

[tieflyer]

So in an effort to reduce chances of oxygenated beer, will this idea work?

Fill keg with co2(to what pressure?)
Take off gas post and put racking cane hose down to bottom.
Rack beer into keg displacing co2
Put post back on
Chill
Carb up
Drink after a week or so.

Will this remove the oxygen from keg when u hook it up to tank and then release pressure?

Will oxygen fill keg when I take off gas post and rack in beer?

 

[myndflyte]

Without doing a closed transfer, this is about the best way to do it. Although here are some suggestions.

I would just pump CO2 through the open lid because if you pressurize it, you'll need to release the CO2 to open the keg. Other than that, after you rack and close it up, I'd crank it up to 30psi to fill the headspace and then pull the pressure release valve. I generally do this 3 or 4 times. That should remove most of the oxygen that may have gotten in there during transfer.

 

[McKnuckle]

Pipe the fermenter's airlock output to the keg's liquid port during fermentation, and hook up a blow-off tube to the keg's gas port leading to a jar of water. Use quick disconnects for both. This provides plenty of CO2 to not only fill, but purge the keg, all without pressure. The keg ends up full of CO2.

Remove all of this when ready to transfer, and rack beer to the keg through the liquid post. Pull the pressure release valve during this process to allow gas to escape while the keg fills.

 

[tieflyer]

Pipe the fermenter's airlock output to the keg's liquid port during fermentation, and hook up a blow-off tube to the keg's gas port leading to a jar of water. Use quick disconnects for both. This provides plenty of CO2 to not only fill, but purge the keg, all without pressure. The keg ends up full of CO2.

Remove all of this when ready to transfer, and rack beer to the keg through the liquid post. Pull the pressure release valve during this process to allow gas to escape while the keg fills.

Ok I’m dumb, But how do I hook up airlock to tubing?
To transfer later on use racking cane to a quick disconnect on liquid post?

 

[Vale71]

You might as well save your CO2 and do an open transfer. By pressurizing the keg with CO2 you're not removing any air, it takes quite a lot of purge cycles to do that. As you vent it before removing the gas post (unless you'd like to lose an eye in the process...) you'll remove some air but considering that transfer takes a long time the atmosphere inside the keg will be 100 air again so you'll have achieved basically nothing.

 

[IslandLizard]

Alternatively to @McKnuckle's suggestion to purge your keg during fermentation (with fermentation CO2), you can perform a 100% liquid pre-purge on the keg.

Then fill the keg through the liquid out post, using a QD with your racking/siphon hose connected to it.
Of course, the racking cane or siphon and attached tubing needs to be primed (pre-filled) with beer, before attaching to the keg, to prevent air from entering that way.

The essence is, once the keg has been 100% purged (by fermentation gas or liquid pre-purge), don't let any air enter. The lid remains on until your next cleaning.

 

[McKnuckle]

But how do I hook up airlock to tubing?

With a standard 3 piece airlock, take out the upside down cup thingie inside it. It sits on top of an open plastic tube. I can't recall the specific inner diameter silicone tubing required, but there's a common variety that fits snugly over that tube. The other end fits just as nicely on a male MFL-equipped quick disconnect (use a hose clamp).

 

[IslandLizard]

the upside down cup thingie inside

Is called the "shuttle."

I can't recall the specific inner diameter silicone tubing required

The airlock stem is 1/2" OD and takes 1/2" ID tubing.

Best is NOT to use silicone tubing for that, as it's almost 100% O2 permeable. IOW, to oxygen it looks as if nothing is there.
Now you could wrap silicone tubing with Kapton (Teflon) tape to make it oxygen impermeable.

Or better/easier yet, use O2 barrier tubing (e.g., EVA barrier tubing).
In a pinch use regular vinyl tubing, which is still somewhat O2 permeable, and not ideal, unless wrapped with Kapton tape.

 

[McKnuckle]

Best is NOT to use silicone tubing for that, as it's almost 100% O2 permeable.

Great! Another thing I have to replace... Well anyway, tubing material notwithstanding, the process does work!

 

[tieflyer]

Is called the "shuttle."


The airlock stem is 1/2" OD and takes 1/2" ID tubing.

Best is NOT to use silicone tubing for that, as it's almost 100% O2 permeable. IOW, to oxygen it looks as if nothing is there.
Now you could wrap silicone tubing with Kapton (Teflon) tape to make it oxygen impermeable.

Or better/easier yet, use O2 barrier tubing (e.g., EVA barrier tubing).
In a pinch use regular vinyl tubing, which is still somewhat O2 permeable, and not ideal, unless wrapped with Kapton tape.

So if I use same tubing I use for keg to facet it will get oxygenated?

 

[IslandLizard]

So if I use same tubing I use for keg to facet it will get oxygenated?

Aerated, but yes. Resulting in oxidation of your beer over time.

That's the main reason many of use are using (the fairly stiff) Bev Seal Ultra 235 tubing or switching over to the newer (much more flexible) EVA Barrier tubing for BOTH beer and gas lines.

For those lines, use the applicable Duotight or John Guest Push-to-Connect adapters for ease of handling and connecting. EVA Barrier tubing can be stretched over barbs with some heating and swaging.

 

[catalanotte]

By pressurizing the keg with CO2 you're not removing any air

Because CO2 has a much higher density than air, doesn't the CO2 in the keg drop to the bottom and displace air out the top as you fill the keg? I certainly understand that anything that involves removing the keg lid is not 100% closed and free of air, but this approach seems to get pretty close and I haven't noticed any oxidation off flavors, even after a couple months in kegs. I typical fill kegs with starsan to the very top and push it out with CO2, but then open the lid to fill from bottom with a gravity transfer. I have always trusted that I am filling the keg under a blanket of co2 and (relatively) safe. I would like to pressure fill but just don't have the ability from a Big Mouth Bubbler.....I can barely keep the lids on them during fermentation.

 

[Vale71]

Sorry, we're all out of CO2 blankets...

That's a hard to die myth, gases mix readily with each other and they never "float" unless constrained in a balloon or a blimp.

 

[DavidWood2115]

My chemistry is over 40 years old, but I found this web page helpful in refreshing my intuition of gas diffusion: 9.4 Effusion and Diffusion of Gases – Chemistry

 

[tieflyer]

My chemistry is over 40 years old, but I found this web page helpful in refreshing my intuition of gas diffusion: 9.4 Effusion and Diffusion of Gases – Chemistry

Boy that was miles over my head, probably why I flunked chemistry.

 

[ApolloSimcoe]

Oh Man, I love the Blanket debate!

 

[McKnuckle]

I typically fill kegs with starsan to the very top and push it out with CO2, but then open the lid to fill from bottom with a gravity transfer.

This kind of defeats the purpose of your purge. Next time, keep the lid on, and transfer via gravity through the liquid port using a quick disconnect. Open the PRV after the transfer begins to allow displaced gas to escape. This at least keeps the keg 99% sealed, and produces a small amount of positive pressure exiting the keg so O2 will not push its way in.