Dominic T. wrote:
> ... All of mine are unglazed (glazed tend to crack internally no
> matter how much care is taken). ... they build up deposits (which
> many Japanese see as a good thing), they rust, ...

I wouldn't use a glazed one; when the glaze chips off, it might wind up
in my gullet. I do have a big one that sits on the wood stove in winter;
I rarely pour from it, but it's nice to know that hot water's always to
hand.

On the latter point: I wonder if, with regular brewing use, a coherent
organic film might form and passivate the iron surface? This certainly
happens with other cast-iron cookware, and is why a seasoned pot or pan
shouldn't be scrubbed down to clean metal. It would be more likely if
the pot used for brewing is also used for boiling, hence exposed to
direct heat that would enhance polymerization and bonding of the
carbonaceous film to the cast iron.

-DM