Is it REALLY TRUE? E61 Espresso Machines

In this video, I show that maybe espresso machines with the group E61 can have precise and stable predictable, provided that they are not Heat Exchangers.

I also show how the group E61 works, and the difference between a Heat Exchanger, and a Single or Dual Boiler with E61 group, explaining why I believe that the unpredictability is due to the Heat Exchanger system and not the E61 group.

Also in this video, you can see one of the measurement that I made in my ECM Classika PID after letting it heating for more that 2h30, which according to Lance Hedrick should let it unpredictable.

Check also my website if you are interested in mods and more coffee geek info: https://espressohackers.com/

I also have 3D Models available for free here: https://makerworld.com/en/@espressoha...