We will get in a ZPM 240V espresso machine for anyone interested to come and try, as while it lies at the opposite end of the espresso ideology spectrum to us I;
(1) have a huge amount of respect for anyone who sets out to make something (it can be a challenge at times), and
(2) if you are a disciple of the doctrine that precise water temperature control is the only path to espresso salvation i have long thought that the only way you could achieve this is with very fine water channels and lots of energy that you can ramp up & down very rapidly in order to quickly move the brew temp up/down in real time
Despite the fact that many people poo-poo thermablock because it is found in low cost machines i think they lack understanding in making such criticism. It is not the thermablock design that is flawed, it is the penny pinching execution of the design. So if these ZPM guys throw some thought and resources at the thermoblock design, and it looks from a distance as though they have, i think it will work very well
It could be further embellished by replacing the aluminium tube encasing element with a copper one, as you find in the magnificent MoccaMaster coffee brewer that only goes pop after 15 years or more of hard daily use, but hey, its easy to criticism almost anything
Another challenge for thermablock machines is they are susceptible to limescale due to the narrow water channels in the thermablock, but i think this is a bit of an unfair criticism as limescale will kill anything, kettles, irons, espresso machines, etc. You’ve just got to ensure you don’t put hard water into any espresso machine in my view. if you have soft water you don’t know how lucky you are!
I think the ZPM guys are onto a winner – by passing a small volume of water over an element with hopefully lots of grunt they have the best chance of delivering water to the coffee puck at a precise, and presumably varying through the shot, temperature. its very clever engineering for sure and looks like delivering a machine that is accessible to a large number of people
learn more about ZPM here; http://zpmespresso.myshopify.com