I'm considering getting one of those "Therminator" style wort chillers as an upgrade to the coil. I plan on gravity feeding the wort through and pumping back into the kettle until my wort is nice and lukewarm. The specs seem impressive, but it also looks like this thing would be hell to clean, and a bit annoying to sanitize, and I can't help but think bits and pieces of hops would easily clog this thing. Am I being paranoid?
Unless you're careful with filtering, plate chillers can and do clog up with debris. Any debris that's trapped during transfer needs to be backflushed out by connecting the wort inlet to the water supply. The high pressure usually pushes out most of the debris, but it's still necessary to bake the chiller in the oven every few batches, and maybe run caustic soda through it once a year to clean out any resident crud.
Here's a pic of an unused shirron plate chiller cut open
The amount of gunk trapped is usually it's not enough to significantly stop the flow, but I've had flow trickle to next to nothing on more than a few batches. For example, I recently tried whirpooling through the plate chiller, and flow ground to a tiny trickle after a few minutes. I was using hop-bags, but still hop pellets and trub can make it into the chiller.
A hopback makes a great filter and pretty much stops any trub from reaching the chiller. You can build your own from a canning jar, or buy them ready made for about $125.
I'm scaling up to 10 gallon batches and looking to buy a new chiller. I will pass on plate chillers this time round.
Also from the same thread:
Brad Smith had John Blichmann on the BeerSmith podcast recently and they discussed cleaning and sanitizing these things. Seems like a non-issue to me after hearing John describe it. You just back-flush with hot water, then PBW, then Star-San and call it a day. Do it immediately after using it to prevent crud from building up. Those I know who have therminators have had no issues with keeping them clean nor have they experienced any infections.