The lever or piston coffee machine, whatever you prefer, is fascinating and recognizable, the long lever with the plastic or even wooden handle, which the barista raises or lowers, is one of the symbols of “once upon a time everything was better “
But what is this machine? And how does it work?
It will be clear to you that the concept of an espresso machine provides that a pressure pushes the water against the coffee with force, extracting all the substances of our powder in a restricted and full-bodied emulsion. If in modern machines the pressure is given by an electric pump, in lever machines this is given manually, by the barista who actually pushes the piston.
The procedure requires the barista to first raise the lever to take the water from the boiler, extract the steam and create the right pressure, then lower it to extract the espresso.
Creating the right pressure and modulating it during extraction is the beauty and the difficulty of this machine. If the pressure is too strong, the water will pass quickly and we will have a pale watery espresso. If, on the contrary, the pressure is weak, the water will pass slowly and our espresso will be bitter and burnt.
Therefore, to use the lever machine well, it takes time to train and sensitivity to “feel the pressure” which results in patience and many terrible expresses before reaching a good quality; but once learned, many swear that no other machine will give us better coffee.
There is some truth, even if an automatic machine is infinitely more comfortable and stable.
Source: Il caffè espresso italiano