changing kegs - turn valve off?

[ronnieramone]

I work at a bar and have an ongoing debate, that has offered no satis*******, definitive solution thus far.

Should you turn the valve off on the co2 tank before changing kegs?

I say, you should. Everything I can find on the subject online says:
"WARNING : Always turn off the Co2 when changing barrels of beer."
or
"Turn gas OFF when changing kegs, cleaning hoses or as soon as the keg is empty."

However, the bar manager says you shouldn't shut off the valve, and that they've been doing it that way for years. So I asked a friend who is a brewmaster in Vegas, and he says you don't need to shut it off either, unless you have a bad seal somewhere, but otherwise it "shouldn't hurt anything" to leave the gas on.

Now, I'm no expert, so I am going to have to go with their saying its okay to leave the gas pressure on while swapping out kegs, but for some reason it just seems wrong to me.

When I change the keg on my personal kegerator at home, I always shut the gas off and perform routine cleaning of the system, but in a busy bar environment, often there is not enough time for a proper cleaning. It seems like they shorten the steps to make it as quick as possible. One way to shorten the process is to leave the gas on.

Now, does anyone have more information as to WHY it would be better to do it one way or the other? Why does every website warn me to turn the gas off when changing kegs if it doesn't really matter? Are there any safety concerns with leaving the gas on? Are there any benefits to doing it my way and turning the gas off first?

Any information would be appreciated. Thank you.

[doug ellis]

I am sure there are a number of ways we connect and disconnect. I like you at home turn off co2, disconect old keg and clean, coupler, faucet, and beer line.
When I put in the new keg however I do turn on the co2 before connecting the coupler.
Every bar I have ever been in never bothered turning off co2, and I have been in a few. Mostly because of time, they don't clean their own lines anyway, places that I asked said that the distributor cleaned lines and the such ( they said that not me ).

[TAPMAN]

Unless the keg has a twin probe coupler, which very few kegs use anymore, or a golden gate style coupler, that even fewer or none use anymore, there is no need to shut the gas valve off, The gas is shut off when the handle is lifted.

[BrewGuru]

100% with TAPMAN on this one

Unless the keg has a twin probe coupler, which very few kegs use anymore, or a golden gate style coupler, that even fewer or none use anymore, there is no need to shut the gas valve off, The gas is shut off when the handle is lifted.

In modern draft systems there is absolutely no need to shut off the gas when swapping out the kegs.

The older systems will vent gas rapidly if decoupled, but all modern couplers ('D','S','A','U','G' and 'M1500' couplers) are designed so that there is a positive seal on the gas in line when the coupler is in the decoupled position (handle up at an angle relative to the valve position).

The only possible reason to turn the gas off is if the coupler will sit for any length of time because there might be a TINY leak over time with the internal o-rings letting some gas by, this should not be a problem with any MM Stainless Steel coupler but cheaper makes and brass containing parts can oxidize and flake and form slight deposits...

If the coupler is removed and then re-installed in relatively short order, there is no problem leaving the gas on. I know of some who even hold the coupler and quickly burst some CO2 out of the coupler by lowering the handle when changing kegs in order to blow off anything on the probe seal or had splashed up inside if the kegs were moved substantially...