Would this work? Siphoning from a keg

I'd like to try lagering in corny kegs, since they take up considerably less footprint in my freezer. However, one problem to be addressed is how to siphon the beer out of the keg when ready to carbonate.

Yes, I know I could just carbonate in the same keg, but I want to leave the yeast and sediment behind. I'll be using a keg with a liquid dip tube with an inch or so cut off the end to siphon the beer off the trub and yeast cake.

I know the easiest way would be to simply connect up the CO2 and "push" the beer out the liquid tube. However, that seems like a waste of a lot of CO2 to me. So I got the idea of trying to siphon out the dip tube. But how to get the siphon started (short of somehow connecting the autosiphon to the liquid out post)?

Here's my idea. What if I assemble a siphon tube from some simple beverage line and ball lock liquid quick-disconnect, with nothing on the other end of the beverage line. I'd set the source keg on an elevated surface, and connect the siphon line to the liquid out post, draping the open end into the destination keg sitting on the floor. I'd then apply a couple PSI of CO2 to the source keg to get the flow started, then open the pressure relief valve (to vent remaining CO2 and let in air to fill the vacuum as the beer level drops)

In theory, the beer should just keep flowing until the beer level in the source keg drops below the opening of the liquid dip tube and it loses siphon, right?

If that worked, it would save me a lot of CO2. So, would that work?

Most people just carb and dump the first couple of pints, the liquid is drawn from the bottom so you'd be dumping the yeast/trub first and be left with clean beer.

It will probably work. If you wanted to save even the tiny bit of CO2 it would require, you could connect a gas QD with another dangling tube and just blow in it really hard to get the siphon started. Or use one of those manual air-mattress pumps or something.

But, CO2 is really cheap - a $20 fill of a 20 lb tank will push something like 250 kegs. I actually use 2 entire kegs worth every time I rack - first to empty the target keg (which is filled with Star San), then to push the source keg into the target. This ensures essentially no exposure to oxygen, which I think is a worthy trade off for 16 cents of CO2.

BobTheFourth said:

If you wanted to save even the tiny bit of CO2 it would require, you could connect a gas QD with another dangling tube and just blow in it really hard to get the siphon started.

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I thought about that, but was worried about contamination and oxidation.

BobTheFourth said:

But, CO2 is really cheap - a $20 fill of a 20 lb tank

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Wow! I wish I lived where you are! Around here, it costs me $35 to fill a 10 lb tank.

Why make things more complicated than they have to be? I just lagered a Biere de Garde for a couple months in a corny. I siphoned the beer out using my auto siphon just like I would with a carboy. It worked great, I even pulled up a little yeast on purpose for bottle conditioning. I kept the tip of the auto siphon down by the end of the dip tube and had very little beer left in the keg .

CreekBrewery said:

Why make things more complicated than they have to be? I siphoned the beer out using my auto siphon just like I would with a carboy.

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LOL! To me, using a separate autosiphon, when you've already got a perfectly good, sanitized dip tube already in place, sounds like the "more complicated" approach!

It sounds like what I'm suggesting should work fine, but it'd be pretty easy to simply test it with some water and a shot of CO2. Maybe I'll do that this weekend with a spare keg, but I believe the physics should be exactly the same as a plain old autosiphon.

I have moved sanitizer between kegs using the same technique with the picnic tap. Never worried about sediment so I have never done it to my beer.