Klean Kanteen has worked great for me. Kept tea that my girlfriend and I made at 7:00 too hot to drink at 13:00. And that was at a snowy mountain lake – the time in between was spent snowshoeing up a mountain trail in the middle of January.

Maybe a silly question, but do you preheat the inside of your thermos with boiling water before adding the coffee from the moka pot?

If not, that small amount of coffee would be quickly cooled by the inner walls of any thermos.