Sterilizing that head space

[kohalajohn]

I"m sure many folk aleady do this, but today's discovery was fun, so thought I'd share.

I've started sterilizing my small kegs by filling them with starsan and pushing it all through with co2. Using fermentation gas when I can, otherwise with bottle gas.

But I know that when I fill the keg with starsan, there remains headspace filled with air. I pour starsan so the keg is overflowing, then put on the lid, but there is always a bit of space I can't quite fill. I can hear it sloshing in the keg.

So I used the liquid post to get at that last annoying bit of head space.

I have a post with pop bottle threads that I use to make soda water in PET bottles. Fill a pop bottle halfway with starsan. screw on the post. Attach a quick disconnect. run a line to a liquid quick disconnect. Snap this onto the keg's liquid post. Lift up the PRV and twist it so it stays open.

Hold the pop bottle above the keg and squeeze. Starsan runs down into the keg. Eventually it comes pouring out the PRV. While it is pouring out, close the PRV.

I was surprised how much empty head space there was. It took half a liter. That's a lot of air that I don't want in my keg. And that I won't any more.

Satisfying.

 

[Indian_villager]

The way a lot of us have been doing it is to cut the dip tube on the gas post so that it is flush with the inside of the keg. Then we put on a gas qd on the gas post and have the keg that is filling with sanitizer tipped enough so that the gas post is the highest point. This way you can do all your purges with less messing about. If you want to add the Duotight flow stopper so that flow is automatically killed once liquid comes out of the gas post. Best of luck
https://www.morebeer.com/products/duotight-flow-stopper-automatic-keg-filler.html

 

[VTMongoose]

There's a very simple solution... Create a liquid to liquid jumper line, push star san from another keg into the keg you're purging, until starsan pushes out the top of the PRV or gas QD (attach a vent to the gas QD as needed if you don't have a pullable PRV on your kegs). Then purge. I have kegs in my house just dedicated to holding starsan for purging kegs. Makes it way easier.

 

[kohalajohn]

Both are nice solutions, thx

If you are filling the receiving keg from a designated supply keg, I imagine the supply keg would have to have a little bit more capacity than the receiving keg. Either a bigger keg, or prefill some starsan into the receiving keg before you start?

 

[kohalajohn]

One more question. Both of you are using gas to push through the entire liquid content of a keg.

I'm not. I am just pouring starsan from my five gallon bucket, into the top of my serving keg , using gravity.

My method uses much less gas. I just use gravity. Is there some advantage to using gas to push through the starsan?

All I can think of is that perhaps my pour method oxygenates the starsan, and you want to avoid that.

But I don't think it matters. Whether the starsan has dissolved oxygen or not, its purpose is just to be a wall of liquid that pushes through the keg, driving the oxygenated air before it and leaving only pure co2 behind it.

The body of liquid acts like the mythical "blanket of carbon dioxide" that we used to believe was a thing. turns out gases mix very quickly, so there is no such thing as a carbon dioxide blanket.

But while gases mix very quickly, it takes a long time for a gas to dissolve in a liquid.

And also, I think not enough time for any dissolved oxygen in the starsan to come out of solution and contaminate the empty space behind it. Certainly not with pressurized co2 pushing against it.

thoughts?

 

[FloppyKnockers]

I just fill the keg half way and use half the StarSan. Invert the keg for a few minutes, them upright for a few minutes.

 

[kohalajohn]

I just fill the keg half way and use half the StarSan. Invert the keg for a few minutes, them upright for a few minutes.

the the
Yes that would certainly sanitize it. But I'm thinking more about the complete removal of oxygen. The initial responders have got me curious about that.

 

[VTMongoose]

I guess either I wasn't clear or you're overthinking what I'm doing. Let's say I have a corny keg I just cleaned and I want to purge it with CO2. The process starts with me filling it with 5 gallons of water and add the ounce or whatever it is of Starsan and give it a shake. I hook up my dedicated "starsan" keg to it which contains starsan and CO2 under pressure, using my liquid-to-liquid jumper, push starsan into it (what, about 0.2 gallons or so?) until it comes out the PRV. Then I grab another keg that needs to be purged and push the starsan into that, topping off as needed from the dedicated starsan keg. By definition each purge only costs me 5.2 gallons of CO2. A 20 pound CO2 cylinder contains 168 cubic feet = 1,256 gallons of CO2.

Trust me, purging bottles for bottling wastes WAY more CO2 than kegging. This is the most efficient way to purge kegs.

I have attached a confusing image showing me purging a bunch of kegs at once. Notice the liquid to liquid jumper lines (one ordinary, one using the Kegland fittings) and gas lines.