We quite like KeyKegs. We wish they cost a little less, or at least that we could find a more cost effective way of getting them transported from Germany. But still, the bag-in-a-ball type of thing is handy and the non-returnable nature cuts costs in other areas.
We can put the beer into KeyKeg with minimal filtering, after carbonating by secondary fermentation in our tanks. It's difficult to find a reason, from this brewers point of view, why the beer in KeyKegs is any different from that in cask. The only disadvantage I can see is that it is difficult to vent off a KeyKeg if the beer is more fizzy than desired1.
In just about 2 weeks from today we'll be pitching up at Leeds to serve beer from KeyKeg. I hope, if I get it all sorted, I may, just for the novelty, seve some of it through handpull.
Meanwhile, here is Jules and I messing around with various human powered compressed air generators.
KeyKeg dispense using foot-pump from Hardknott Brewery on Vimeo.
1However, it is not impossible to reduce carbonation levels by venting. I'm planning a tutorial video on dealing with Craft Keg when it gets too carbonated.