Espresso machine

An espresso machine forces hot water through a tightly packed bed of finely ground coffee — the “puck” — at high pressure, in around 25–30 seconds, to pull a small, concentrated shot of Espresso topped with crema, the tan foam layer. The modern standard pressure is roughly nine bar (about nine times atmospheric pressure, ~130 psi), delivered by a pump.¹² That single number — nine bar — is the dividing line between real espresso and merely strong coffee, and almost the whole history below is the story of how the industry arrived at it.

The coffee is held in a portafilter: a handled metal basket that twists and locks into the group head, the fixture on the front of the machine where water meets coffee.³ The portafilter is the piece a barista carries around, knocks out, and re-loads all day.

The steam era (1884–1940s)

The first machines used steam pressure, not a pump, and they brewed in bulk rather than by the cup.

• 1884 — Angelo Moriondo, of Turin, patented a steam-driven “instantaneous” coffee-making device (Italian patent of 16 May 1884).¹³ A boiler pushed hot water and steam through a large bed of grounds at only about 1.5–2 bar — enough for a café to brew a batch fast, but nowhere near modern pressure. It is widely called the first patent for a steam coffee machine, though it made bulk coffee, not single shots.³
• 1901 — Luigi Bezzera, a Milanese maker, applied (19 December 1901) for a patent on machinery to “prepare and immediately serve” coffee, granted in 1902.¹ His advance was the single-cup group head with a portafilter, which turned bulk brewing into individual servings — the reason he is credited with the first true commercial espresso machine.³⁴
• 1903 — Desiderio Pavoni bought Bezzera’s patent and founded La Pavoni, beginning industrial production in Milan.¹³ Pavoni’s machines added a pressure-release valve and a steam wand — the nozzle that shoots pressurised steam into milk, still used for steaming and latte art today — and anchored early Italian bar culture.³

These steam machines shared a flaw: to make pressure you boiled water hard, and water that hot scorches the coffee. The shots were bitter and burnt, which is exactly the problem the next generation set out to fix.

The lever revolution and the birth of crema (post-WWII)

The breakthrough was to separate heat from pressure. Instead of using steam to both heat and push, use water at a sensible brewing temperature and add the pressure mechanically — with a spring-loaded lever.

Achille Gaggia, a Milanese café owner tired of burnt coffee, built the spring-piston lever machine: the barista pulls a lever down, which compresses a large spring; releasing it lets the spring drive a piston that forces water through the puck at roughly 8–10 bar.¹⁴ This was the first time coffee was brewed at what we now call high pressure — and the high pressure did something no steam machine ever had: it emulsified the coffee’s oils into crema.⁴ “Pulling a shot” and the very word for a lever machine (“pulling”) both come from this pull-down action.

Two consequences worth holding onto:

• Because a compressed spring pushes hardest at the start and eases off as it relaxes, lever pressure is not flat — it spikes high (Counter Culture cites peaks up to ~14 bar) and then declines across the shot.⁴ That naturally falling curve is, in hindsight, the first pressure profile — a theme the machines of the 2000s would return to deliberately.⁴⁵
• Shot time dropped from around a minute on steam machines to roughly 25–45 seconds, and espresso became a distinct drink rather than “strong coffee.”⁴

To verify

The Gaggia lever’s patent date. This wiki’s research report dates Gaggia’s lever patent to 1938, with commercial production after the war (commonly given as 1947–1948, when Gaggia founded his company and sold the first machines). Wikipedia instead dates the development to 1945.¹ The sources agree the machine reached cafés just after WWII and that Gaggia is the crema pioneer; they disagree on the underlying patent year. Treat “1938” versus “1945” as unsettled until a patent-office record is checked.

The pump and the nine-bar standard (Faema E61, 1961)

In 1961, Ernesto Valente of Faema introduced the E61 — named for the 1961 solar eclipse (“E” for eclisse) — and it is the machine most people picture when they picture an espresso machine.¹³ Two ideas made it the template every modern machine still follows:

• An electric rotary pump replaced the barista’s arm, delivering a constant ~9 bar at the push of a button. Where the spring’s pressure sagged over the shot, the pump held pressure steady — and, crucially, made it repeatable regardless of who was working the bar.¹² James Hoffmann credits the E61 with establishing nine bar as the fixed constant of espresso.²
• A heat-exchanger group drew brew water on demand through the steam boiler, giving better thermal stability and the iconic chrome group head still sold under the “E61 group” name today.³

This is the pivot from lever to pump — from pressure you supply with your body to pressure the motor executes identically every time.

Controlling temperature (La Marzocco, 1970 onward)

Pump pressure solved consistency of force; the next problem was consistency of heat. La Marzocco, founded in Florence in 1927 by brothers Giuseppe and Bruno Bambi, led here.⁶

• In 1939 La Marzocco registered the first patent for a horizontal boiler, letting group heads sit in a neat row along the front of the machine — better ergonomics for a busy bar.⁶
• In 1970 it patented the GS, described as the first dual-boiler machine: one boiler for brew water and a separate one for steam, so a barista can set the brewing temperature independently of the steam pressure and hold it stable.⁶
• Later machines added saturated groups (group heads thermally bolted straight to the brew boiler to kill temperature swings) and PID controllers — electronic thermostats that hold water temperature inside a narrow band, introduced on the GB/5.⁶

Temperature is a quiet variable but a decisive one: a few degrees changes how much of the coffee dissolves, which is the same extraction lever that grind size and ratio pull on.

Pressure profiling (2000s–2010s)

Pressure profiling means deliberately shaping the pressure across the shot rather than holding a flat nine bar — typically somewhere in the 0–9 bar range.⁵ A profiled shot can run distinct phases: a gentle pre-infusion (low-pressure soak to wet the puck evenly), a ramp up to peak, a hold, and a controlled decline.⁵ The idea is not new — the old spring lever did a crude version by accident (see above) — but modern machines let the barista program or paddle it on purpose, tuning extraction to a given roast or grind.⁵

The commercial revival came around 2009–2010 with machines such as the Slayer and the La Marzocco Strada.²⁵ La Marzocco presented its pressure-profiling technology at the 2009 SCAA event; the paddle-controlled Strada EP followed, and the semi-automatic Strada EE in January 2014.⁶ The Strada uses a variable-speed gear pump whose voltage — and therefore pressure — the barista can change mid-shot, which is exactly what James Hoffmann describes when he dates the machine to “around 2009, 2010.”²

To verify

Pre-espresso steam devices (1822 and 1843). The research report describes a steam device by Louis Bernard Rabaut shown to the French Academy of Sciences in 1822, and a commercial steam brewer by Edward Loysel de Santais in 1843, as the earliest pressure coffee machines.³ These come from a single blog account and were not independently confirmed here; the operating pressures and extraction times are not given. Stated as a claim, not established fact.

To verify

The “nine bar” origin. Nine bar is the universal standard, but why it is nine (rather than eight or ten) is often told as tradition rather than measured optimum. The E61’s ~9 bar figure is well documented;¹² the deeper claim that nine bar is physically ideal is not something the sources here establish.

Related

• Espresso — the drink the whole machine exists to make
• Achille Gaggia — the inventor behind the spring lever and the birth of crema
• Latte art — poured on top of espresso, using the machine’s steam wand
• Extraction yield · Brew ratio · Coffee grinding — the three dials, besides pressure, that decide how a shot tastes
• James Hoffmann — whose “Understanding Espresso” series is a primary explainer of pressure and the E61
• La Marzocco — the maker behind dual boilers, PID and the pressure-profiling Strada
• David Schomer — the Seattle café owner who retrofitted PID temperature control onto his own machines
• Francesco Illy · Illy — the founder who built the 1935 illetta, an early machine that likewise separated water heating from pressure rather than relying on steam
• Third wave coffee — the movement that pushed espresso from a fixed ritual toward a tunable, measured process

Official links

• Official site — Specialty Coffee Association — the industry body that publishes espresso and equipment standards

Footnotes

1. Espresso machine — Wikipedia — confirmed via WebFetch; source of the Moriondo 1884 patent, Bezzera’s 1901 filing / 1902 grant, Pavoni’s 1903 purchase and La Pavoni, Gaggia’s 8–10 bar lever, the Faema E61 (1961) pump, and the La Marzocco GS (1970) as the first dual boiler. ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹

2. Understanding Espresso: Pressure (Episode #6) — James Hoffmann ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶

3. A history of the espresso machine — Perfect Daily Grind ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹

4. The History Of Espresso Machines — Counter Culture Coffee ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶

5. Pressure Profiling in Espresso Machines: What It Is And Why It Matters — Cliff & Pebble ↩ ↩² ↩³ ↩⁴ ↩⁵

6. La Marzocco — Wikipedia — confirmed via WebFetch; source of the 1927 founding by Giuseppe and Bruno Bambi, the 1939 horizontal-boiler patent, the 1970 GS dual boiler and saturated groups, PID on the GB/5, and the Strada pressure-profiling machine (2009 SCAA presentation; Strada EE January 2014). ↩ ↩² ↩³ ↩⁴ ↩⁵