Fermentation vessels for closed transfer?

[aangel]

I'm looking for ideas for "ideal for my purposes" fermentation vessels. I want:
-able to ferment full 5gal batch
-cleanable
-stackable (?), and most critically:
-able to do closed (pressurized) transfer!

I'm aware of corny kegs, but they're overpriced now, and ideally I'd like to use my corny kegs to serve, not ferment.

Glass carboys are dangerous to pressurize so that's a no.
Plastic jugs/better bottles are an option but take up a lot of space. ideally i'd have something i can put in a keezer or keg fridge.

Any ideas? I'm also looking for half-size (say 3gal or even 1.5gal) containers to do super-experimental batches with

 

[trentm]

I'm looking for ideas for "ideal for my purposes" fermentation vessels. I want:
-able to ferment full 5gal batch
-cleanable
-stackable (?), and most critically:
-able to do closed (pressurized) transfer!

I'm aware of corny kegs, but they're overpriced now, and ideally I'd like to use my corny kegs to serve, not ferment.

Glass carboys are dangerous to pressurize so that's a no.
Plastic jugs/better bottles are an option but take up a lot of space. ideally i'd have something i can put in a keezer or keg fridge.

Any ideas? I'm also looking for half-size (say 3gal or even 1.5gal) containers to do super-experimental batches with

Pressure transfer has been great for me as I do 40 L batches and am getting toward old. Since I brew Belgian Pales I like to bulk age in a secondary. I ferment (among other things) in a modified old style 15 gallon keg (first image below) and pressure transfer to a 40 L modified milk can (second image below). After aging, the beer is then pressure transferred to a bottling vessel (or keg in your case). A 25 L (6.6 gallon) milk can like this could serve your purpose and is available at: http://hambydairysupply.com/xcart/product.php?productid=18357&page=1. As you can see they are a little pricy and require the modifications in the second image (a gas inlet in the lid and a ball valve near the bottom) in order to do a pressure transfer. While the clamp on lid with a silicone gasket is said to be liquid tight, it is not gas tight but a couple of small C-clamps take care of that. Sanitation can be achieved by adding a small amount of water (~2 L) to the vessel and boiling for ~15 minutes (do not boil with the lid clamped down). These vessels are very sanitary inside with no seams. It would be nice if they were a little thicker but would add to price. I am always careful not to add too much pressure due to the thinness of the vessel but it takes very little to do the transfer. Although they would dent easily, with care I expect mine last for ever.

I have liked this so well I plan on getting another one. Next time I will have a sanitary tri-clamp ferrule welded in for the bottom outlet.