Manual Espresso MachinesManual espresso machines are sometimes also called piston or lever espresso machines. These are the first machines that produced modern day espresso. The design of the first piston espresso machine was patented in 1938 by Achille Gaggia. The first commercially manufactured machine of this type came in the mid 1940s.
Piston espresso machines are usually really beautiful to look at. They can be treated as a functional work of art. These machines can, in the right hands, produce outstanding espresso. But they are not easy to use. You have many different variables to control so the learning curve is very high. Often people buy a manual espresso machine without knowing how much time and effort is necessary to learn to pull a good shot of espresso. The machine then ends up serving as an expensive decoration.
There are two different mechanisms: the direct piston and the spring piston.
Direct piston machines
With the direct piston machines you manually force the water through the coffee grounds by pulling the lever. You move the lever up from it's resting position - that allows the water to go into the brewhead. You then force the water through the grounds by pressing the lever back down. You need to do it in such a way that the correct pressure is applied all the way through the shot. That's not easy. It requires a lot of practice and also some arm strength.
These are the most hands on espresso machines that you can get.They are great for people who are really serious about the art of espresso. The most common direct piston espresso machines are La Pavoni Europiccola, La Pavoni Professional, Olympia Cremina, Gaggia Achille or Gaggia Factory.
Spring piston machines
In these machines a spring is used to operate the piston. The resting position of the lever is up. You compress the spring by pushing the lever down. This allows the water into the grouphead. You then allow the lever to go back up as the spring slowly uncoils.
The pressure that the spring applies to the piston is not uniform - it starts at about 9 bars when the lever is all the way down and then gradually reduces to about 7 bars as the lever heads back to the resting position. This is quite unique as non-manual espresso machines have the pressure constant throughout the shot. Some people believe that this gradual lowering of the pressure actually makes a better espresso.
Spring piston machines are easier to use than the direct piston type because the spring controls the pressure instead of you. Obviously that also means that you loose control of one variable that can make your shot even better. But they still leave you with a plenty of other factors to control.
Spring piston mechanism is used in most commercial manual espresso machines. Some examples of the spring piston machines are Elektra Micro Casa a Leva or Capucio King.
Further ReadingBest Espresso Machines: Manual Models
Planning to Buy Espresso Machine