[Podo]

Thanks everybody, for confirming what I thought.  I'm glad my instincts were good, for a change!! 

[pinnah]

I purge all the air out of the keg with CO2 before filling it (which is just good anti-oxygen transfer practice), then top it off to make sure the seals are tight.

Sorry if this is a silly question,
but can someone explain to me how this is practiced?

If I open the lid to rack into the keg, does this not allow oxygen in?

[Hokerer]

If I open the lid to rack into the keg, does this not allow oxygen in?

I believe the thinking goes along the line that CO2 is heavier than "air" thus, if you're gentle when you open the lid, gravity should keep the CO2 in the keg until it's displaced by the beer you rack into it.

[tom]

Sorry if this is a silly question,
but can someone explain to me how this is practiced?

If I open the lid to rack into the keg, does this not allow oxygen in?

Yep, sure does. Gases mix. Maybe not instantaneously, but they will.
I sanitize my kegs by filling them with StarSan and then transferring it to another keg with CO2. This leaves the keg full of CO2. Then I fill it from the beer-out post and let pressure off through the pressure relief valve (you can just open it or you can unscrew it until the beer flows).

[corkybstewart]

I purge all the air out of the keg with CO2 before filling it (which is just good anti-oxygen transfer practice), then top it off to make sure the seals are tight.

Sorry if this is a silly question,
but can someone explain to me how this is practiced?

If I open the lid to rack into the keg, does this not allow oxygen in?

Don't open the keg lid.  Pressurize with CO2, then use the pressure relief valve if the lid has one, or depress the poppet on the gas in post with a key or knife.  Let the pressure(CO2) bleed off and repressurize.  repeat a couple of times.

[hopfenundmalz]

Sorry if this is a silly question,
but can someone explain to me how this is practiced?
If I open the lid to rack into the keg, does this not allow oxygen in?

Yep, sure does. Gases mix. Maybe not instantaneously, but they will.
I sanitize my kegs by filling them with StarSan and then transferring it to another keg with CO2. This leaves the keg full of CO2. Then I fill it from the beer-out post and let pressure off through the pressure relief valve (you can just open it or you can unscrew it until the beer flows).

I am lazy, so I have a hose attached to a gas in connector, and the hose is in a jar of sanitizer to make an air lock.  Then I can do other things, and no O2 should get in.  Still do a couple of purges and put some pressure on to seat the lid.

[oscarvan]

Or, to keep it simple, just "pour" some CO2 in the keg when filled and just before you put the lid on. This can be done two ways: With a hose on the CO2 bottle with an in-line shut off. The other one is a trick I learned from one handy brewer.... he carries one of these:



Minus the ball connect and uses it as a six shooter in his back pocket..... just a squirt in the keg and hoppa, the lid goes on.

Or, just thought of this.... (I have one of those) you could just leave the ball connector on, hook it up and shoot in some CO2 with the blow off vent open, that would purge it....

There's a lot of ways to do this......none of them too complicated.

[gordonstrong]

I purge all the air out of the keg with CO2 before filling it (which is just good anti-oxygen transfer practice), then top it off to make sure the seals are tight.

Sorry if this is a silly question,
but can someone explain to me how this is practiced?

If I open the lid to rack into the keg, does this not allow oxygen in?

Yes but not to where the beer is. CO2 is heavier than air. Rack using a tube into the bottom of the keg. The CO2 gets displaced as the beer level rises. Any air that starts mixing with the CO2 is getting pushed back out.  After it's done, you blast it with more CO2 to get rid of any air that got in.  Contact time is minimal and not lasting. Covering the opening with some foil or Saran wrap while you're filling can limit air intake as well. The main idea is to limit oxygen contact and to make sure none remains when done.

[pinnah]

Thanks very much for the explanations fellas!