The Industrial Revolution was in full swing by late 19th/early 20th century. In the factories of Italy, employers noticed the increased productivity of their workers after coffee breaks. However, each coffee would take 5 to 15 minutes to make - and that’s before the workers even have their drink.

In Milan in 1901, Luigi Bezzera made improvements and patented his versions of what was the world’s first single-serving espresso machine.

It was a big boiler half filled with water which was heated by a flame and could brew a coffee in as little as 30 seconds. As the water reaches boiling point, it creates steam which in turn builds the pressure inside. The ‘barista’ would then release a valve which allowed the steam pressure to push the hot water through a dose of coffee and into a cup.

He soon discovered that the regular coffee grind was too coarse. With this pressure, the hot water rushed through the coffee grounds with no resistance compared to the previous brews. So a finer grind was used to allow a longer coffee to water contact time, or extraction, which produced a more desired flavour.

The result was that coffee breaks were reduced. The workers got their boost, and the employers got their workers for longer. Bezzera still makes quality coffee machines today, including the Eagle Dome which is a throwback to the original espresso machine.

In 1938, Gaggia developed a steam-less coffee machine with a high pressure ‘piston mechanism’. The result was a crema in the espresso’s which became the focus of their advertisements. The term ‘pulling shots’ came from the act of pulling the lever down to begin the extraction.

In 1939, La Marzocco patented the first espresso machine with a horizontal boiler. It allowed the ability to have multiple group heads.

In 1961, Faema introduced the E61 group head, which is still used in many machines today as standard. More importantly, they also used an electrical pump which consistently flowed water through a heat exchanger before contacting the coffee in the group head. A heat exchange gets its temperature by travelling through the boiler rather than from the boiler. When boiler water empties, it then gets replaced by cold water which the machine needs to work hard to re-heat it. The heat exchanger allows the water in the boiler to remain which meant making coffee had little effect on temperature stability.

The pump, pushing at a consistent 9 bars of pressure, allowed for a smooth, consistent extraction. Before the introduction of a pump, water pressure through coffee would fluctuate between 4 and 11 bars. In 1970, La Marzocco patented their first series of dual-boiler machines. These allowed for separate chambers heated to a specific temperature to match the desired profile of the coffee. The other is used only for steam to texture milk and to withdraw hot water for teas and some espresso beverages. The argument for these dual boilers is that they can maintain a consistent temperature for brewing coffee to the desired profile without fluctuation.

A heat exchange will consistently be 88-94 degrees through the group head, where the dual boiler can almost no variance.