7wt
Expedition Leader
Living in what amounts to new Italy I can tell you how the vast majority of Italian's make their espresso here, with a stainless stove top Bialetti. I have an aluminum one and it took about a week to build up some really nasty oxidation on the inside of the boiler. My future mother in law has a stainless one that has been used daily for longer than I could say and it still looks great.
http://www.bialettishop.com/MusaMain.htm
http://www.bialettishop.com/MusaMain.htm