How quickly does CO2 sink to bottom of the keg?

[Judochop]

Before I rack a beer into a keg, I hit the keg with ‘some’ CO2. Usually at about 3-5 psi for about 5-10 seconds.

Then I wait ‘some’ time for the CO2 to sink to the bottom and replace the O2 before I start my siphon. Usually about 30 seconds.

Am I waiting long enough in either or both steps?

(I realize that putting in the CO2 through the beer side diptube would assure an instant bottom layer of CO2. But I don’t do that.)

 

[Changeduser123]

Check out one of the "lake nyos experiment" videos on youtube to have an idea of how fast the CO2 falls:



You can go directly at 2:30 min.

 

[Spartan1979]

(I realize that putting in the CO2 through the beer side diptube would assure an instant bottom layer of CO2. But I don’t do that.)

Why not?

 

[snccoulter]

OK that is kinda cool reading about the lake. What people can do.

 

[Judochop]

Why not?

Switching tubes around on a keg after I've santized doesn't sit well with me. And I've run into snags with the method of putting the CO2 into the beer post without letting it 'lock down'. (The snag being that I slip and do let it lock down.)

 

[DanPoch]

If you use hoses and posts with the flare fittings you can swap out the gas post at the end of the gas line with a beverage post to add the CO2. That would avoid having to switch teh dip tubes in the keg.

 

[RickWG]

Before I rack a beer into a keg, I hit the keg with ‘some’ CO2. Usually at about 3-5 psi for about 5-10 seconds.

Then I wait ‘some’ time for the CO2 to sink to the bottom and replace the O2 before I start my siphon. Usually about 30 seconds.

Am I waiting long enough in either or both steps?

(I realize that putting in the CO2 through the beer side diptube would assure an instant bottom layer of CO2. But I don’t do that.)

As a chemist (Ph.D.) since you are putting the gas in under pressure you are probably creating disturbance in the keg (no liquid right?). You would have an even distribution as soon as you were done filling the keg.
Now if you were talking co2 to the bottom of a filled keg with no shaking that would be an interesting equation.

 

[Judochop]

As a chemist (Ph.D.) since you are putting the gas in under pressure you are probably creating disturbance in the keg (no liquid right?).

Not under pressure. The keg is empty. The lid is off (probably sitting in sanitizer solution). I usually have a piece of sanitized foil covering the keg opening to avoid falling spiders and sudden sneeze attacks from getting in, but it's nothing that would cause pressure to build.

I pump in the CO2 for a few seconds, and then wait a half minute or so before siphoning in the beer. I just want to be sure I'm pumping it long enough, and then waiting long enough for it to go all the way down.

So to speak.

 

[rcrabb22]

Before I rack a beer into a keg, I hit the keg with ‘some’ CO2. Usually at about 3-5 psi for about 5-10 seconds.

Then I wait ‘some’ time for the CO2 to sink to the bottom and replace the O2 before I start my siphon. Usually about 30 seconds.

Am I waiting long enough in either or both steps?

(I realize that putting in the CO2 through the beer side diptube would assure an instant bottom layer of CO2. But I don’t do that.)

I break down and clean my kegs each and every time I empty them. I sanitize my kegs after I am done cleaning and rinsing. That involves total reassembly of the parts after they have been sanitized. I fill the keg with about a gallon of starsan, seal up the lid, slosh it about, then charge with 15lb CO2 and use a picnic tap to drain the starsan back into the 5 gal storage bucket I keep.

There is residual pressure and CO2 left in the keg that will sink to the bottom during the month or so it sits before refilling.

 

[Judochop]

I break down and clean my kegs each and every time I empty them. I sanitize my kegs after I am done cleaning and rinsing. That involves total reassembly of the parts after they have been sanitized. I fill the keg with about a gallon of starsan, seal up the lid, slosh it about, then charge with 15lb CO2 and use a picnic tap to drain the starsan back into the 5 gal storage bucket I keep.

There is residual pressure and CO2 left in the keg that will sink to the bottom during the month or so it sits before refilling.

Good strategy. :thumbs up:

 

[RickWG]

Not under pressure. The keg is empty. The lid is off (probably sitting in sanitizer solution). I usually have a piece of sanitized foil covering the keg opening to avoid falling spiders and sudden sneeze attacks from getting in, but it's nothing that would cause pressure to build.

I pump in the CO2 for a few seconds, and then wait a half minute or so before siphoning in the beer. I just want to be sure I'm pumping it long enough, and then waiting long enough for it to go all the way down.

So to speak.

Hmmmm. As the gas is leaving the line it is going at a rather high rate (psi). this is causing a vortex in the keg and mixing the gas rather than displacing the atmosphere. In lab we did this same kind of thing with argon under a laser light to watch the mixing of gas. it would go down one side and back up the other side leaving a practically unmixed portion in the middle. If we pressurized the container and allowed the gas to come to a entropic mixture and then purged the gas it would suck out more of the atmosphere since the ratio of co2 to o2 was higher.

atmospheric pressure (what you are doing) 1 part co2 and one part O2 = 50% O2
under co2 pressure 100 parts co2 and one part O2 = 1/100th or 1% O2 after purging

Unless you could just pour the co2 in like in the video you would mix your gasses the pouring in of gas would displace the o2 as the heavier co2 filled from the bottom.

 

[jeepinjeepin]

Any CO2 purge is better than no CO2 purge. RDWAHAHB.

 

[Judochop]

If you use hoses and posts with the flare fittings you can swap out the gas post at the end of the gas line with a beverage post to add the CO2. That would avoid having to switch teh dip tubes in the keg.

I don't know what's dumber. That I never thought of this, or that the first time I read the post I didn't bother to understand it.

I guess a good dumb answer would be 'both'. But I get it now. And it's what I'm going to do. Thank you.

So, based on another's response in here, will 'vortexing' of the gases be less of a problem if the CO2 goes in through the beer line? I'm supposing that the slower the gas goes in (lower PSI) the better.