In the bustling cafes of 17th-century London, a bowl of coffee was a leisurely affair, a catalyst for hours of debate and intellectual exchange.
Fast forward two centuries, and the world was spinning faster.
In the industrial heartland of Milan, a new kind of demand was brewing: coffee, but without the wait.
This urgent need gave birth not just to a drink, but to an entire philosophy of speed and precision, embodied in a singular, intense pour:
the Espresso.
The very name Espresso doesn’t merely hint at speed; it delves into the essence of its creation.
Deriving from the Italian for “pressed out” or “expressed,” it speaks to the mechanical force that extracts its rich, concentrated essence.
Yet, it also carries a more personal implication: a cup prepared “expressly for you,” a bespoke brew crafted in the blink of an eye for the individual customer.
This marked a profound shift from the batch-brewed coffees of old, transforming a long ritual into a dynamic, personal encounter.
Our journey into the world of Espresso begins not with a delicate cup, but with the clanking of steam engines and the ambition of innovators like Luigi Bezzera.
His 1901 patent introduced the portafilter, the crucial component that would harness steam pressure to force water through finely ground beans.
This was the dawn of a new era, delivering an intense, invigorating shot in mere seconds – a radical concept for a world accustomed to slow percolation.
While lacking the signature golden crema we know today (that would come later with Gaggia’s 1948 lever machine), these early Muted Brass behemoths laid the foundation for the Deep Espresso shot that now defines coffee culture globally.
It was a revolution in a tiny cup, forever changing how we consume, appreciate, and experience coffee.
So lets start right at the beginning:
The Origin Story: Pressure vs. Time
Our Espresso story begins way back in the late 1800s.
Coffee was slow to make, it took 5–10 minutes to brew a cup.
In the bustling port city of Milan, workers were taking to long away from the business to get their coffee that business owners wanted a way to get their workers back to work faster.
There was a machine that inventor Angelo Moriondo (1884) used steam with, that instantaneously brewed coffee but it was very big and to be honest not really how coffee should be brewed.
Then along came Luigi Brezzera (1901) who took the steam engine and added a cradle with a handle (a Portafillla) so that the steam would pass through the grounded beans and produced a quicker way of brewing.
Trouble was that Senore Brezzera was an enginneer not a business man, and 4 years after his refinement along came a shrewd Desiderio Pavoni ( 1905) who saw the value in this enhancement and talked Luigi into buying the patent of the machine and he made a small adjustment with the temperature and pressure of the steam being pushed through the grounds which actually made a much better coffee to drink.
Then being the astute business man marketed the new machine as the first “Bar” coffee machine, under his companies name La Pavoni. The two men continued to work together, mass producing machines.
“Bar” being the measure of the pressure the water was taking to get through the coffee grounds.
His Bar pressure was around 1 0r 2 compare that to the 9 Bar recommended today to get that perfect crema topped Espresso and it tells you how far the Espresso machines have progressed.
Although the coffee was plain black strong and slightly burnt taste, it was a big step towards a better cup of coffee.
But way back when, they knew nothing about “Crema” it was just plain black coffee. the precursor to the Espresso.
The 1948 Breakthrough of Pressure
It was in 1948 that engineering met science in the forn of Achille Gaggia another inventer who this time took pressure to another level by realising that coffee grinds needed high pressure to produce a top to the black liquid in the form of Crema.
The force of the water being driven through the grinds emulsified the oils in the coffee that produced the golden foam like topping.
When Gaggia took this new product out to the shops and markets he had to call it Caffe Crema, as he people thought the topping was a defect.
Evolutionary Timeline of Bar Pressure:
The evolution of pressure in coffee machines moved from low-pressure steam (1–2 bar) that Luigi Brezzera produced with his steam machine in the late 19th century to the 9-bar standard established in the 1940s by Gaggia, and finally to modern variable pressure upto 20 bar.
- 1884–1940s: The Steam Era (1–2 Bar)
- Early machines, such as those by Angelo Moriondo (1884) and Luigi Bezzera (1901), used steam pressure to force water through coffee.
- These machines could only generate about 1.5–2 bars of pressure.
- The result was more similar to strong, hot filter coffee rather than modern espresso, and the lack of pressure often led to a bitter taste.
- 1945–1960s: The Lever Era and the “Crema” Revolution (8–10 Bar)
- Achille Gaggia introduced a piston-driven lever machine in 1947–1948, which separated the boiler from the brewing pressure.
- This innovation allowed baristas to manually generate 8–10 bars of pressure.
- This higher pressure was the key to producing the thick, foamy layer known as “crema,” effectively defining the modern standard for espresso.
- 1961: The Motorized Pump (Constant 9 Bar)
- The Faema E61, released in 1961, replaced the physical lever with a motorized pump, providing a consistent 9 bars of pressure.
- This removed the need for manual strength and ensured consistent extraction quality.
- 1970s–Present: Advanced Control (9–20+ Bar)
- Modern machines, starting with advancements in the 1970s, introduced PID controllers and dual boilers, allowing precise temperature control alongside consistent pressure.
- Commercial/Prosumer Machines: While 9 bar remains the standard for optimal extraction, many machines are capable of higher pressure (up to 15-20 bars) to ensure stability, though the “9-bar rule” remains the gold standard for taste.
- Modern Innovation: Contemporary, high-end machines (e.g., La Marzocco Strada, 2009) now feature pressure profiling, allowing the user to vary the pressure throughout the shot, beginning with low pressure for pre-infusion and moving up to 9 bars or more.
Why 9 Bar?
The 9-bar standard was largely an accidental outcome of Gaggia’s 1940s engineering (based on piston size and strength) that happened to be the ideal pressure for balancing flavor and extraction within a 25–30 second window.
Concentration over Volume
The invention of the Espresso machine changed the “physics” of coffee.
Because the water is forced through the grounds at such high pressure, you extract the same amount of caffeine and flavor in 1 ounce of liquid as you would in a large 8oz cup of drip coffee.
It is a “reduction,” much like a sauce in cooking.
The “Crema” Factor
The golden foam (crema) is the soul of an espresso.
If you put 1 oz of espresso into a giant 12oz mug, the crema would spread out so thin that it would disappear.
The small, narrow cup keeps the crema thick and traps the aromas inside so you can smell them as you sip.
The “Standing” Culture
In Milan, where this started, an Espresso was meant to be drunk “al banco” (at the bar).
It was a 30-second ritual.
You ordered, the barista “pressed” it out expressly for you, you drank it in two sips, and you left.
A large 6oz or 8oz cup would take too long to drink and would get cold before you finished it.
“While the 17th-century ‘Penny Universities’ of London were places to sit for hours over a bowl of coffee, the 20th-century Italian Espresso changed the ritual into a fast, standing encounter, served in a tiny ‘demitasse’ to preserve its heat and intensity.”
