Manual or semi-automatic machines offer more control of shot quality. Because when to cut the shot (brew time) is a critical variable, which is often adjusted shot-by-shot, semi-automatic machines are often preferred over automatics, though some machines are automatic. Manual machines are more popular in Europe, where it is more common to drink straight espresso.
The term dual boiler is used narrowly for machines with two separate boilers, and more broadly for what are more properly called dual heater (DH) machines, featuring a boiler for brewing and a separate thermoblock (TB) for heating brew water to steaming temperature – opposite to HX machines, where the boiler is at steaming temperature and is cooled to brewing temperature.
“This is the same coffee maker that I bought years ago. And it’s even the same price. Yep — they do still make things like they used to. And they last forever. It’s super simple, super reliable, compact, and cheap. There are a lot of places where we can spend money, but a simple cup of coffee doesn’t have to be one of them. Once you get the amount of water and coffee figured out to your taste — simply do that. No K-cup, nothing to recycle, fits the car cup holder. And the coffee stays hot in the mug.”