Could I ferment in this? Possibly as a secondary?

I have a 4 carboys full and bubbling away at the moment, which is all of them. The issue I have is that I have a cream ale about half way through primary and I want to rack that to secondary when the time is right, and reuse that yeast cake for a double IPA that I already have all the grain for. I have an uncut Sanke with the spear removed just for fermenting, but I don't want to, or even thing it's wise to use a 15.5 gallon vessel for a 5-6 gallon batch. BUT after seeing the article on brewing cider with a college budget, I'm reminded that I have a 5 Gallon army water jug in the garage that I take hunting. I know I would need to rig an airlock, which is no problem.

Would it not be worth it or add off flavors to the beer? Ultimately I think I may just end up buying another carboy, but don't want to since I don't know if I'm going to get into a bottle neck like this again.

OR, I just thought of this as I'm typing, should I rack it to a corny keg and just fasten an airlock on that? It's the closest beer I have to being ready, so I could just rack to a second available corny when secondary is done.

This question turned out to be a lot longer than I thought.

If fermentation is almost complete (near expected final gravity) you could rack to the corny and not rig up an airlock.

Interesting, I didn't know that. I was thinking that I could just attach a ball lock to the gas side and run a tube to can/cup or water.

Having drank gallons of water from army jugs in the past years, I would not rack my beer into them. They impart that strong plastic flavor to water, and I would fear that this off-flavor would transfer to my beloved beer. I don't mind plastic-tasting water, but beer.....

If you choose to rack it into that jug, please let us know how it turned out. Who knows, I might be tempted to bring some homebrew on FTX next time

Cheers !

Black

HAHA, I think I'm just going to use the corny. But I may do a test batch just to see.

I agree with Gartywood, if you can wait till you hit your fg (or have hit it) then just rack into the the keg, no need to secondary unless you planned on adding something else