In 1909, Luigi Giarlotto’s machine showcased the first-known heat exchanger.
In 1950, Beniamino Rota’s Condor machine brought baristas closer to controlling the pressure, and therefore the temperature, of the water in a heat exchange machine. Rota was the first to patent an espresso machine that featured an electric pump.
A thermostat was used to regulate the temperature on the earliest espresso machines. It contained a wax pellet that melted within a sealed chamber and expanded at a set temperature. This in turn cracked open a spring-loaded valve to release the pressure.
The heat source for the first espresso machines was gas or wood. A barista had to manually shut off,