During my research I have seen everything from well insulated fancy stainless exhaust tubing to plain old 24 gauge galvanized duct piping used to vent steam from the boil kettle.
I would like to do the cheapest yet most effective thing, and certainly dont like the idea of galvanized duct work rusting around my beer, yet stainless is so expensive. HELP.
Also do any of you worry about boiling the kettle over, into the steam tube? should this system be easily taken apart for regular cleaning? I have a forced air natural gas burner system.
Also what about steam condensing inside the tube and running back into the kettle, is this a problem? or should the pipe be angled down and away, rigging something akin to the "spit" valve on a trumpet, to let the condensation drip out?
I built a fairly simple but effective condensor with some ss tubbing the thin gauge self sealing tubbing you can find easily.
I goes up from the center of the kettle and elbows a little more than 90 degrees to keep the condensed liquid from running back into the kettle. to a 3 way where I drilled a hole and put a small spray nozzle and hose hook up and a down tube. It works great.
Ive seen it done with a blower in the top to suck out the air it too is effective a bit noisey but effective.
You can try to run a copper coil along the inside of the down tube and return the waste water to the hot liquor, effiecency in the brewhouse.
I find once the foaming of the wort reaches the tube it blocks the steam outlet and will cause a boilover, so in the begining of the boil I have to stand there for about 10 minutes and switch of the heat as the foam gets close, after that it stabilizes and I can go do other things.
Of course the tubing gets dirty and a good CIP will clean it out.