> steaming the water to heat it rather than using a kettle or water from the espresso machine's boiler made a better drink

Was it Mr Hoffmann[0]? He has a decent explanation for why this might be the case too (and does an experiment later which points to it maybe being dissolved gases.)

[0] https://www.youtube.com/watch?v=0HdzJz_evNw

Yes, that's the video. He doesn't seem to be a fan of americanos. It's one of my favorites so I'm pretty interested in new ideas for one of the most basic drinks.