First kegging. Is offgassing required?

[westpointbrewery]

So I have about 13 to 14 gallons of beer fermenting right now and am getting ready to force carbonate it in a Sanke keg. However, I have a couple questions regarding the actual kegging process. First I plan on taking the ball lock and spear assembly out of the keg and carefully filling the keg trying to avoid getting excess oxygen into the beer. Then I am going to put the ball lock and spear back on. My question though is that I will have about 2 gallons of head space that is just air. So do I need to offgas that air to prevent the oxygen from getting in the beer? If so how would i do that in a sanke keg?

 

[brewmasterpa]

you have to purge the air or you will have oxidized beer. not sure how to do it on a sanke keg, you might google that or perhaps somebody else will respond to your thread that knows, but i do know you have to purge it immediately. the only batch of beer ive ruined has been from not purging before i stored it for lagering.

 

[Bobby_M]

You can simply flood the headspace with CO2 and carefully reinsert the spear/valve assembly. Since it's heavier than air, it will fill the headspace and push the air out.

 

[ajwillys]

On a Sanke keg, you can purge by just pulling the little ring on the coupler. This will blow out the air without the need to remove the spear, coupler, or anything. I do it while connected to the CO2 and just purge, let it refill, purge, let it refill, etc... for about 10 times.

The other thing I do (not specific to a sanke) is prefill the keg with CO2 so that there's no oxygen in there beforehand.

 

[Bokonon]

I know some homebrewers that do this. Here's what they do:

Remove spear
Hot water rinse/PBW soak/Hot water rinse
Add sanitizer
Re-install spear
Pressurize with co2 and purge a few times to get most of the air out
Roll keg around to coat all surfaces with sanitizer
Use sankey tap to remove sanitizer right before filling
Use same sankey tap to fill keg with beer
After filling, purge headspace with co2 just to be safe

by forcing your sanitizer through the sankey tap you are sanitizing the spear and all the fittings. IIRC you'll need to remove the liquid check valve in the tap in order to fill through there

 

[ajwillys]

Bokonon,
This sounds like a very interesting idea, I may have to try this. What about the fact that there's a few ounces of sanitizer left if you use dip tube to remove it?

I'm actually working on a process in the back of my head to clean a Sanke keg without removing the spear so this interests me. I would use a modified coupler for insertion/removal of the various liquids.

 

[Bokonon]

Bokonon,
This sounds like a very interesting idea, I may have to try this. What about the fact that there's a few ounces of sanitizer left if you use dip tube to remove it?

I'm actually working on a process in the back of my head to clean a Sanke keg without removing the spear so this interests me. I would use a modified coupler for insertion/removal of the various liquids.

I'm not sure I would worry about a little bit left, not sure what they do about it. I know they use starsan.

Two thoughts about it though:

1> I'd think the co2 should push it out completely, or at least almost all of it
2> If it doesn't all get pushed out, the keg could be inverted and hook the lines up in reverse. Push the co2 into the liquid side, and let the liquid flow out of the gas side

If your going to clean the keg without removing the spear (or if you do remove the spear and are using a pump), you should be inverting it. If your leaving the spear in for the cleaning you'd want to pump into the liquid side and let it drain out of the gas side.

If your going to ferment in the keg its probably best to pull the spear to make sure all the gunk comes out, if your just serving from the keg then I think leaving the spear in is a good way to go. I know several breweries that only pull the spear after a certain number of uses for deep cleaning and inspection

 

[westpointbrewery]

I would love to fill my keg with the spear/ball valve in place but how do you get the beer through the tap? My fermenter has a drum valve on it, so i was just going to use gravity to fill the keg. Is there some way to hook the fermenter up to the tap and allow the beer to flow into the keg while the keg is under pressure?

 

[ajwillys]

You would have to have greater pressure pushing the beer in than the pressure inside the keg. Usually, this is accomplished by bleeding off some pressure as its filling.

I was thinking about this last night as I was filling/cleaning a couple kegs and I started thinking that my current method is really easy and I should just leave well enough alone. I don't think I'm going to mess with it.