Quote Originally Posted by 12vdc View Post
I'm using zojirushi brand, the one with ceramic coating. No metallic aftertaste compared to regular SS flask.

There is a secret coating applied to aluminum cans in beverages that eliminates the metal aftertaste.
errr,
it's a "secret" in that the consuming public is not universally aware of it,
but the thin plastic inner coating is common knowledge in the aluminum can beverage industry.
there are interesting youtube videos on how it can be... exposed.

aluminum is a reactive metal, and it has to be insulated in acid-containing foods like soft drinks, etc.
it also probably prevents that metallic taste...

la lang.