Does beer in a keg carbonate from the top down?

[724b]

I'm playing around with a technique for serving beer from the top down instead of the bottom up. It's done through a float attached to flexible tubing.

This is making me wonder if beer carbonates at the top of the keg and that carbonation works it way down.

This makes some sense to me, but I was wondering what others thing.

With the top down technique, it seems as though the beer carbonated very quickly.

 

[Homercidal]

It has to. The CO2 comes in at the top and is put into solution by the pressure and mixes with the liquid beer. How fast it moves through the beer is a whole nother question! You may not be able to discern a difference in carbonation with any common device.

 

[kellynm]

I agree. The beer should carbonate at the top surface of the beer since that is the interface between beer and CO2. Now there is a high concentration of CO2 at the top and nothing at the bottom... a gradient exists. The dissolved CO2 should begin to distribute evenly throughout the beer until equilibrium is reached, which should be based upon the regulator pressure. I think....

 

[pjj2ba]

Once the CO2 gets into the beer, it will diffuse quite rapidly throughout all of the beer, certainly within minutes if not even quicker

 

[724b]

Once the CO2 gets into the beer, it will diffuse quite rapidly throughout all of the beer, certainly within minutes if not even quicker

That's probably true when using the shake to carb method, but I'm thinking this may occur more slowly when the keg is stationary.

 

[IffyG]

I can't imagine the diffusion of CO2 from top to bottom is so slow that it warrants an over-engineered solution to draw beer off the top.

 

[724b]

I can't imagine the diffusion of CO2 from top to bottom is so slow that it warrants an over-engineered solution to draw beer off the top.

I agree. It's just a side benefit. Also, the solution is pretty simple.

http://www.homebrewfinds.com/search?q=widge