Does anyone have any solid knowledge about the physics and/or chemistry of expresso machines, and in particular, the pump handle found on (it appears to me) the more expensive ones?
Some years ago I bought an espresso machine at a dept. store; my recollection is that it probably cost around $150 to $200--not cheap, but not horribly expensive either. I returned it when it did not make espresso that tasted "like the espresso of my youth".
When I returned it, by chance, I ran into the sales rep for the company, and she confided to me that to make really, really good espresso, you needed a machine with the pump handle on it. I've noticed that such machines are few and far between in commercial establishments.
Anyone have any info on this, or maybe a reference to a site or book that has additional info?