{ "id": "history-of-the-espresso-machine", "url": "https://coffearium.org/entries/history-of-the-espresso-machine/", "license": "CC-BY-4.0", "title": "History of the espresso machine", "summary": "How the espresso machine developed from steam-boiler bar machines to spring levers, hydraulic groups and pumps with heat exchangers, dated from patent records and historians, with the disputed firsts marked.", "domain": "history", "kind": "History", "stage": "brew", "topics": [ "history", "equipment" ], "topicSections": {}, "lang": "en", "status": "verified", "reviewer": "Coffearium verification pass", "lastVerified": "2026-10-27T00:00:00.000Z", "literatureSearched": "2026-10-27T00:00:00.000Z", "updated": "2026-10-27T00:00:00.000Z", "added": "2026-10-27T00:00:00.000Z", "brief": [ "Luigi Bezzera of Milan filed a US patent for a single-cup coffee machine on 10 June 1902, assigned to Desiderio Pavoni; it was granted in 1903.1", "The La Pavoni Ideale of 1905 was the first espresso machine to enter production, according to a historian and a museum exhibition.2,3", "Achille Gaggia filed a patent for a piston tap for espresso machines in 1947; his spring-lever machine followed in 1948.2,3,5,6,7", "The Faema E61 appeared in 1961; a design museum and a historian describe a motor-driven pump at nine bars and a heat exchanger in the boiler.2,4,13", "From 1960, Ernesto Valente patented a motor-driven pump, a delayed-infusion valve and a boiler heat exchanger with thermosiphon circulation to the group.10,11,12" ], "quickFacts": [ { "label": "Steam-boiler era", "value": "1902–1940s; Bezzera US patent filed 1902, La Pavoni Ideale 1905" }, { "label": "Spring lever", "value": "Gaggia patent filed 1947; machine introduced 1948" }, { "label": "Hydraulic group", "value": "Cimbali patent, Italian priority 7 Apr 1956" }, { "label": "Pump and heat exchanger", "value": "Valente patents, Italian priorities 1960–1961; Faema E61, 1961" }, { "label": "Later patents (examples)", "value": "Secondary boiler per group, stored pressure curves, PID control (2017 priorities)" } ], "aka": [ "Espresso machine history", "History of espresso", "Lever espresso machine history" ], "linkTerms": [ "history of the espresso machine", "Faema E61", "La Pavoni Ideale" ], "related": [ "espresso-machine", "espresso", "moka-pot", "reading-a-shot", "espresso-machine-care", "milk-and-milk-drinks", "history-of-brewing", "eras-and-waves-of-coffee", "coffeehouses-from-mecca-to-europe" ], "contested": [ "Date of Bezzera’s patent: the US patent was filed on 10 June 1902 and granted on 28 April 19031; a museum exhibition dates his patent to 1901, which may refer to an earlier Italian filing.2 No Italian patent record was consulted for this entry.", "Gaggia’s first patent: a design museum exhibition states that Gaggia applied for a patent for a steamless machine in 1938 and for a second one in 1947.4 The patent record consulted for this entry dates from 19476, and a historian and a second museum date the machine to 1948.2,3 The 1938 application could not be checked.", "Pressure of the first steam machines: a patent background puts saturated-steam boiler pressure at about 1–1.5 bar7, and a museum exhibition gives 1.5 bar2; a coffee historian gives a somewhat higher range for the La Pavoni Ideale of 1905.3", "Pressure of Gaggia’s lever machine: around 9 bar according to a coffee historian3; 10 bar according to one museum exhibition2 and 8–10 bar according to another.4", "Pump of the E61: a historian describes an electrical volumetric pump13, a design museum a motorised pump.4 Valente’s 1961 heat-exchanger patent prefers a centrifugal pump12, and a 2017 patent describes his 1960 pump patent as a rotary-pump machine.7 No source consulted states which patent covers the E61." ], "corrections": [ { "date": "2026-10-27T00:00:00.000Z", "change": "Brief on the Faema E61 now attributes the pump, nine bars and heat exchanger to one design museum and a historian, not two museums.", "reason": "The MUMAC exhibition gives the E61 date only, not its pump or heat exchanger." }, { "date": "2026-10-27T00:00:00.000Z", "change": "Gaggia’s lever pressure (around 9 bar) is now given beside the 10 bar and 8–10 bar of two museum exhibitions and listed in Contested; the historian’s 1.5–3 bar for the Ideale is no longer given as a number, and the 1–1.5 bar steam pressure is paired with the museum’s 1.5 bar.", "reason": "Number rule; the Folmer textbook never carries a number alone, and a patent background on earlier machines is Tier B." }, { "date": "2026-10-27T00:00:00.000Z", "change": "Swiss filing and publication dates of CH 262232 removed; the 1947 date now rests on the Italian priority in AT 179620 B.", "reason": "The Swiss register record could not be reopened in verification." }, { "date": "2026-10-27T00:00:00.000Z", "change": "The uncited date (1884) and place (Turin) for Moriondo’s patent removed; the stagnation statement and the Cimbali piston statement corrected to what AT 237214 B and US 2,878,747 say.", "reason": "No source consulted gave them; the patents attribute the effects differently." } ], "sources": [ { "id": "s1", "title": "Coffee-making machine (US Patent 726,793)", "authors": "Bezzera, L. (assignor to D. Pavoni)", "year": 1903, "publisher": "United States Patent Office; filed 10 June 1902, granted 28 April 1903", "url": "https://patents.google.com/patent/US726793", "tier": "A", "quote": "the quantity of coffee necessary for a single cup is prepared separately, so that fresh coffee is always served.", "quotes": [ { "text": "which chambers are adapted to contain the gas-burners or other source of heat.", "for": "boiler heated through tubular heating chambers" }, { "text": "a perforated diaphragm situated between the discharge-nozzle of the deliverycock and the coffee-receptacle", "for": "delivery cock, bell and perforated diaphragm" }, { "text": "The said notches serve for the reception of handles of the cup q, provided with a perforated bottom.", "for": "filter cup with handle and perforated bottom" } ], "scope": { "claim": "description", "context": "US patent specification and claims for a boiler-fed bar machine; inventor in Milan, assigned to Desiderio Pavoni.", "checked": "2026-10-27T00:00:00.000Z" }, "accessed": "2026-10-27T00:00:00.000Z" }, { "id": "s2", "title": "Design Espresso (online exhibition)", "authors": "Museu do Café, with Museo della Macchina per Caffè (MUMAC)", "publisher": "Google Arts & Culture", "url": "https://artsandculture.google.com/exhibit/design-espresso/hgLiplh4OeKBJg", "tier": "B", "quote": "Desiderio Pavoni acquired the patent of this invention and, in 1905, produced the first espresso machine", "quotes": [ { "text": "In 1901, Luigi Bezerra patented a vertical machine that heated water in a boiler", "for": "1901 date for Bezzera’s patent (spelled Bezerra in the exhibition)" }, { "text": "high temperatures of the steam reached only 1.5 bar", "for": "steam pressure of the early machines" }, { "text": "Achille Gaggia produced in 1948 in collaboration with Faema workshop, the first machine with the", "for": "1948 lever machine, built with the Faema workshop" }, { "text": "water would pass through a filter at a pressure of 10 bar", "for": "10 bar for Gaggia’s lever machine" }, { "text": "It consisted of a spring lever connected to a piston which, manually reduced, caused compression of the boiling water", "for": "spring lever and piston" }, { "text": "Faema, Milan, 1961, E-61 model.", "for": "E61 date" } ], "scope": { "claim": "description", "context": "Museum exhibition text with object captions (the url redirects to story DwXhplh4OeKBJg); history narrative, no references given.", "checked": "2026-10-27T00:00:00.000Z" }, "accessed": "2026-10-27T00:00:00.000Z" }, { "id": "s3", "title": "We Consumers – Tastes, Rituals, and Waves", "authors": "Morris, J.", "year": 2017, "publisher": "In: Folmer, B. (ed.), The Craft and Science of Coffee, Academic Press, ch. 19 (pp. 471–472 cited)", "url": "https://doi.org/10.1016/B978-0-12-803520-7.00019-0", "doi": "10.1016/B978-0-12-803520-7.00019-0", "tier": "B", "quote": "In 1948 Achille Gaggia introduced the lever machine that utilized a manually operated spring-loaded piston to blast the water through the coffee under around 9 bars of pressure.", "quotes": [ { "text": "The La Pavoni Ideale of 1905 was the first so-called espresso machine to enter into production", "for": "La Pavoni Ideale in production in 1905" }, { "text": "Gaggia promoted this as entirely new beverage, giving it the name of Crema", "for": "Crema Caffè" } ], "scope": { "claim": "description", "context": "Historian’s textbook chapter on coffee consumption; Italy, 20th century; cites the author’s earlier work.", "checked": "2026-10-27T00:00:00.000Z" }, "accessed": "2026-10-27T00:00:00.000Z" }, { "id": "s4", "title": "Passione Italiana: The Art of Espresso (online exhibition)", "authors": "Museum of Design Atlanta (MODA), with CUBE Design Museum", "publisher": "Google Arts & Culture", "url": "https://artsandculture.google.com/story/YgVxzyyXKVR5Iw", "tier": "B", "quote": "Carlo Valente, founder of the company Faema, revolutionized the brewing of espresso with the E61.", "quotes": [ { "text": "In 1938, Achille Gaggia applied for a patent for the first modern, steamless coffee machine", "for": "1938 patent application (single source)" }, { "text": "In 1947, Gaggia applied for his second patent which was for the machine on view here.", "for": "1947 patent application" }, { "text": "was the first machine that could create 8-10 bars of pressure", "for": "8–10 bar for Gaggia’s lever machine" }, { "text": "the E61 used a motorized pump to provide the nine bars of pressure needed for brewing espresso.", "for": "E61 pump and nine bars" }, { "text": "A heat exchanger keeps the water to an ideal brewing temperature.", "for": "E61 heat exchanger" } ], "scope": { "claim": "description", "context": "Design museum exhibition text with object captions; no references given.", "checked": "2026-10-27T00:00:00.000Z" }, "accessed": "2026-10-27T00:00:00.000Z" }, { "id": "s5", "title": "Rubinetto per macchine per la preparazione di caffè espresso (Swiss Patent CH 262232 A)", "authors": "Gaggia, G. A.", "publisher": "Swiss Patent Office (patent register record)", "url": "https://patents.google.com/patent/CH262232A/it", "tier": "A", "tierNote": "Bibliographic record only (title, applicant); the description was not consulted. The record could not be reopened in verification (27 Oct 2026), so the entry gives no Swiss filing or publication date; the 1947 date rests on AT 179620 B (s6), and the lever-type construction on EP 3 653 086 A1 (s7)", "quote": "Rubinetto per macchine per la preparazione di caffè espresso", "quotes": [], "scope": { "claim": "data", "context": "Patent register record (Google Patents); Swiss patent, cited as CH 262232 in a 2017 European patent.", "checked": "2026-10-27T00:00:00.000Z" }, "accessed": "2026-10-27T00:00:00.000Z" }, { "id": "s6", "title": "Hahn für Expreßkaffeemaschinen (Austrian Patent AT 179620 B)", "authors": "Gaggia, G. A.", "year": 1954, "publisher": "Austrian Patent Office; Italian priority 8 August 1947, filed 20 March 1950, published 25 September 1954", "url": "https://patents.google.com/patent/AT179620B/de", "tier": "A", "tierNote": "Bibliographic record only (title, applicant, priority and dates); the description was not consulted", "quote": "Hahn für Expreßkaffeemaschinen", "quotes": [], "scope": { "claim": "data", "context": "Patent register record (Google Patents); Austrian patent claiming an Italian priority.", "checked": "2026-10-27T00:00:00.000Z" }, "accessed": "2026-10-27T00:00:00.000Z" }, { "id": "s7", "title": "Device and process for controlling the extraction pressure of coffee in an espresso coffee machine (EP 3 653 086 A1)", "authors": "Cappellini, D. (applicant Carimali S.p.A.)", "year": 2020, "publisher": "European Patent Office; priority 18 July 2017, published 20 May 2020", "url": "https://data.epo.org/publication-server/rest/v1.2/patents/EP3653086NWA1/document.html", "tier": "A/B", "tierNote": "A for how its own machine is built (secondary boiler per group, stored pressure curves); B for its background on history and earlier designs, including the steam-boiler pressure of early machines (paired with s2)", "quote": "This pressure has a value comprised between about 1 bar and about 1.5 bar.", "quotes": [ { "text": "CH 262232 describes an espresso coffee machine of the so-called lever type", "for": "Gaggia’s Swiss patent as a lever machine" }, { "text": "the pressure is given to the water by a piston manoeuvred through a lever", "for": "piston moved by a lever" }, { "text": "describes an espresso coffee machine where the pressure is generated by a rotary pump", "for": "rotary pump (US 3,119,322)" }, { "text": "all modern espresso coffee machines operate with a pump that directly forces the passage of the hot water", "for": "pumps as the standard" }, { "text": "each dispensing group 10 is physically and hydraulically connected to a small secondary boiler 14", "for": "secondary boiler per group" }, { "text": "a set of predetermined pressure curves that the espresso coffee machine is capable of reproducing autonomously", "for": "stored pressure curves" } ], "scope": { "claim": "description", "context": "European patent application; background section on steam, lever, hydraulic and pump machines; description of a multi-group machine.", "checked": "2026-10-27T00:00:00.000Z" }, "accessed": "2026-10-27T00:00:00.000Z" }, { "id": "s8", "title": "Importance of Espresso Coffee Machine Parameters on the Extraction of Chlorogenic Acids in a Certified Italian Espresso by Using SPE-HPLC-DAD", "authors": "Caprioli, G.; Cortese, M.; Odello, L.; Ricciutelli, M.; Sagratini, G.; Tomassoni, G.; Torregiani, E.; Vittori, S.", "year": 2013, "publisher": "Journal of Food Research 2(3), 55–64", "url": "https://www.openaccessrepository.it/record/70454/files/fulltext.pdf", "doi": "10.5539/jfr.v2n3p55", "tier": "A", "quote": "Aurelia is equipped with an electric pump and a heat exchanger, while in Leva pressure is given by a spring and water is brought to the desired temperature by passing it through a boiler.", "quotes": [], "scope": { "claim": "finding", "context": "Lab comparison of one pump machine with a heat exchanger and one spring-lever machine; pressure and temperature logged during shots; Italy.", "checked": "2026-10-27T00:00:00.000Z" }, "accessed": "2026-10-27T00:00:00.000Z" }, { "id": "s9", "title": "Automatic distributing set for coffee percolators (US Patent 2,878,747)", "authors": "Cimbali, V. (assignor to Officine Cimbali Giuseppe S.p.A.)", "year": 1959, "publisher": "United States Patent Office; Italian priority 7 April 1956, filed 7 September 1956, granted 24 March 1959", "url": "https://patents.google.com/patent/US2878747", "tier": "A", "quote": "Under the impulse of the hydraulic pressure operating on the upper face of piston 11", "quotes": [ { "text": "The pressure of the cold water fed into the inlet E is preferably lowered by a pressure reducer", "for": "mains water pressure drives the group" } ], "scope": { "claim": "description", "context": "US patent specification for a hydraulically driven brewing piston.", "checked": "2026-10-27T00:00:00.000Z" }, "accessed": "2026-10-27T00:00:00.000Z" }, { "id": "s10", "title": "Coffee making machine (US Patent 3,119,322)", "authors": "Valente, E.", "year": 1964, "publisher": "United States Patent Office; Italian priority 8 October 1960, filed 4 October 1961, granted 28 January 1964", "url": "https://patents.google.com/patent/US3119322", "tier": "A", "quote": "it is necessary to create, on the spot, such pressure by means of a pump.", "quotes": [ { "text": "the cost of operating the pump, which also operates during periods of time which do not require the use of pressure.", "for": "pump runs only when pressure is needed" } ], "scope": { "claim": "description", "context": "US patent specification for a coffee machine with a motor-driven pump; inventor in Milan.", "checked": "2026-10-27T00:00:00.000Z" }, "accessed": "2026-10-27T00:00:00.000Z" }, { "id": "s11", "title": "Alternately seating valves (US Patent 3,230,974)", "authors": "Valente, E.", "year": 1966, "publisher": "United States Patent Office; Italian priority 24 September 1960, filed 25 September 1961, granted 25 January 1966", "url": "https://patents.google.com/patent/US3230974", "tier": "A", "quote": "the sealing device 7 opens under a pressure of 1.5 atm.", "quotes": [ { "text": "a desired interval of infusion between the opening of the cock and the distributing of the drink.", "for": "delayed infusion in the distributing head" } ], "scope": { "claim": "description", "context": "US patent specification for a valve in the distributing head (group) of a coffee machine.", "checked": "2026-10-27T00:00:00.000Z" }, "accessed": "2026-10-27T00:00:00.000Z" }, { "id": "s12", "title": "Kaffeemaschine (Austrian Patent AT 237214 B)", "authors": "Valente, C. E.", "year": 1964, "publisher": "Austrian Patent Office; Italian priority 28 November 1961, filed 26 November 1962, published 10 December 1964", "url": "https://patents.google.com/patent/AT237214B/de", "tier": "A", "quote": "Der Motor betätigt eine Pumpe 7, welche vorzugsweise als Zentrifugalpumpe ausgebildet ist.", "quotes": [ { "text": "in welchem ein rohrförmiger Wärmeaustauscher 1 schräg angeordnet ist.", "for": "tubular heat exchanger in the boiler" }, { "text": "Bei stillstehender Pumpe, d. h. wenn kein Kaffee bereitet wird, zirkuliert das Aufgusswasser", "for": "thermosiphon circulation between shots" }, { "text": "man hat auf diese Weise vor dem Beginn der Getränkeausgabe eine Tränkphase des Kaffeepulvers.", "for": "soaking phase before dispensing" } ], "scope": { "claim": "description", "context": "Austrian patent specification for a heat-exchanger coffee machine with a motor-driven pump.", "checked": "2026-10-27T00:00:00.000Z" }, "accessed": "2026-10-27T00:00:00.000Z" }, { "id": "s13", "title": "The Faema E61 Espresso Machine", "authors": "Morris, J.", "year": 2020, "publisher": "Perspectives on History, American Historical Association", "url": "https://www.historians.org/perspectives-article/the-faema-e61-espresso-machine-january-2021/", "tier": "B", "quote": "The E61 drew cold water from an external source, passed it through a heat exchanger situated within its boiler", "quotes": [ { "text": "This was the first commercially successful semi-automatic espresso machine.", "for": "semi-automatic" }, { "text": "an electrical volumetric pump that passed hot water through the coffee under a constant nine bars of pressure", "for": "pump and nine bars" }, { "text": "replacing manually operated levers with an on/off switch controlling delivery", "for": "switch instead of lever" }, { "text": "Previous machines used boilers to heat the water directly.", "for": "earlier machines used boiler water" } ], "scope": { "claim": "description", "context": "Historian’s short article on one machine, Italy, 1960s; no references.", "checked": "2026-10-27T00:00:00.000Z" }, "accessed": "2026-10-27T00:00:00.000Z" }, { "id": "s14", "title": "Espresso coffee machine with improved system for regulating the temperature of the water and method for regulating the temperature of the water in an espresso coffee machine (US Patent 11,517,143 B2)", "authors": "Dionisio, A.; Salvi, G. (assignee La Marzocco S.r.l.)", "year": 2022, "publisher": "United States Patent and Trademark Office; priority 24 March 2017, granted 6 December 2022", "url": "https://patents.google.com/patent/US11517143", "tier": "A/B", "tierNote": "A for how the machine is built; B for its background on known temperature regulation", "quote": "Proportional-Integral-Derivative or Proportional-Integrative-Derivative (PID) controller system", "quotes": [ { "text": "espresso coffee machines which use a closed loop regulating system are known", "for": "closed-loop temperature regulation described as known" } ], "scope": { "claim": "description", "context": "US patent specification for brew-water temperature control in a coffee boiler.", "checked": "2026-10-27T00:00:00.000Z" }, "accessed": "2026-10-27T00:00:00.000Z" }, { "id": "s15", "title": "The Complexity of Coffee", "authors": "Illy, E.", "year": 2002, "publisher": "Scientific American (June 2002), pp. 86–91", "url": "https://www.scientificamerican.com/article/the-complexity-of-coffee/", "tier": "C", "quote": "1961 Ernesto Valente of Faema, an Italian coffee machine maker, designs the archetype of the modern espresso machine.", "quotes": [], "scope": { "claim": "description", "context": "Magazine article; timeline box on coffee history.", "checked": "2026-10-27T00:00:00.000Z" }, "accessed": "2026-10-27T00:00:00.000Z" } ], "markdown": "## Steam machines for one cup at a time\n\nThe first bar machines solved a problem of service, not of flavour. In 1902 Luigi Bezzera of Milan filed a US patent for a coffee-making machine and assigned it to Desiderio Pavoni.1 Its stated aim was to prepare the coffee for each cup separately, “so that fresh coffee is always served”.1 The patent was granted on 28 April 1903.1 A museum exhibition dates Bezzera’s patent to 1901 (see Contested).2\n\nThe machine was a boiler with a tap. Gas burners or another heat source sat in tubular chambers running through the water.1 A delivery cock in the lower half of the boiler led into a bell-shaped conduit.1 A perforated diaphragm spread the water and steam over the coffee in a cup with a perforated bottom, held by handles.1 That cup does the job of the portafilter described in the espresso machine entry.\n\nPavoni acquired the patent and, in 1905, produced the La Pavoni Ideale.2 A historian and a museum exhibition both describe it as the first espresso machine to enter production.2,3 According to the historian, it used pressure to brew a fresh cup “expressly” for each customer, unlike the bulk urns of catering.3 In his account, the coffee still tasted like a concentrated drip brew.3\n\nThe limit was physical. In a steam-boiler machine the pressure depends on the boiler temperature, according to a 2017 patent.7 It puts the pressure of such boilers at about 1–1.5 bar, and a museum exhibition gives 1.5 bar for the early machines.2,7 Raising the pressure meant raising the temperature, and the same patent links water near boiling to a burnt taste.7\n\n## The spring lever separates pressure from heat\n\nThe lever broke the link between pressure and temperature. Achille Gaggia filed a patent for a tap for espresso machines in Italy on 8 August 1947, the priority date of his Austrian patent.6 A 2017 patent describes his Swiss patent for such a tap as a lever-type machine.5,7 In it, a piston moved by a lever and pushed by a spring gives the water its pressure.7\n\nGaggia introduced the lever machine in 1948, according to a historian and a museum exhibition.2,3 The exhibition states that it was produced in collaboration with the Faema workshop.2 The historian gives around 9 bar on the coffee; two museum exhibitions give 10 bar and 8–10 bar (see Contested).2,3,4 The extract carried a head of coffee oils, which Gaggia promoted as a new beverage, “Crema Caffè”.3 A design museum states that Gaggia had applied for a first patent in 1938; no record of it was consulted for this entry (see Contested).4\n\nA lever shot does not hold one pressure. In one study, a spring-lever machine peaked at 8 bar and fell to 2 bar after 26 s, while a pump machine held 9 bar.8 The espresso machine entry covers this comparison.\n\n**Hydraulic groups.** A third way used the water main. Vittorio Cimbali patented such a group, with Italian priority of 7 April 1956.9 In it, mains water pressure, reduced by a valve, acts on the upper face of a piston.9 That piston drives the brewing piston.9 According to the 2017 patent, lever and hydraulic machines wet the coffee at low pressure as the piston rises, before full pressure arrives.7\n\n## The pump and the heat exchanger\n\nThe next step replaced the arm with a motor. Ernesto Valente of Milan filed patents with Italian priorities in 1960 for a machine with a motor-driven pump, run only when pressure is needed.10 A second patent covered a valve in the group that delays the flow, giving “a desired interval of infusion”.11 That valve opens at 1.5 atm (about 1.5 bar, our conversion with 1 atm ≈ 1.01 bar).11\n\nA patent with priority of 28 November 1961 adds the heat exchanger.12 Fresh water passes through a tube inside the boiler instead of being drawn from the boiler itself.12 When the pump is off, the water circulates on its own between exchanger and group (thermosiphon).12 The patent prefers a centrifugal pump and describes a soaking phase before the coffee flows.12\n\nThe Faema E61 appeared in 1961.2,4,13 According to a historian and a design museum, a motor-driven pump gave it nine bars of pressure.4,13 A heat exchanger in the boiler heated the water.4,13 The historian notes that earlier machines heated the brew water in the boiler directly.13 He calls the E61 the first commercially successful semi-automatic machine, with an on/off switch in place of the lever.13 The design museum names Faema’s founder as Carlo Valente.4 No source consulted states which patent covers the E61.\n\n
\n
\n
    \n
  1. Boiler. Water below, steam above; the steam pushes the water out.1,7
    2. \n
  2. Heating chambers. Tubes through the water for gas burners or another heat source.1
    3. \n
  3. Delivery cock. Opens the boiler to the coffee.1
    4. \n
  4. Bell and perforated diaphragm. Spread the water over the coffee.1
    5. \n
  5. Filter cup. Perforated bottom, held by handles.1
    6. \n
  6. Lever. Pulled by the barista; it moves the piston.3,7
    7. \n
  7. Spring. Pushes the piston down.7,8
    8. \n
  8. Piston. Forces the water through the coffee.2,3,7
    9. \n
  9. Water chamber. Filled with hot water from the boiler.8
    10. \n
  10. Coffee in the filter holder.3
    11. \n
  11. Pump. Driven by an electric motor.10,12
    12. \n
  12. Heat exchanger. A tube in the boiler that heats fresh water on its way to the group.12,13
    13. \n
  13. Thermosiphon loop. Circulates water between exchanger and group when the pump is off.12
    14. \n
  14. Infusion valve. Delays the flow; it opens at 1.5 atm in one patent.11
    15. \n
  15. Coffee in the filter holder.12
    16. \n
\n
Three ways of pushing water through the coffee: steam in the boiler (left), a spring lever (middle), a pump with a heat exchanger (right). Dashed lines follow the water. Schematic, not to scale.
\n
\n\n## Later developments\n\nPumps became the norm. A 2017 patent states that modern espresso machines operate with a pump that forces the hot water through the coffee.7 It cites Valente’s 1960 patent as a machine with a rotary pump.7 The vibratory pumps of many domestic machines are described in the espresso machine entry.\n\nLater patents separate brewing from steam. The same 2017 patent describes a machine in which each group has its own small secondary boiler, apart from the main boiler.7 It also stores sets of pressure curves that the machine can replay on its own.7 Another patent with 2017 priority regulates brew-water temperature with a PID (proportional–integral–derivative) controller.14 Its background states that closed-loop temperature regulation was already known.14 No source consulted for this entry dates the first machine with a separate brew boiler or the first PID-controlled machine.\n\n## Milestones at a glance\n\n
\n
\n
    \n
  1. 1902. Bezzera files his US patent (granted 1903).1
    2. \n
  2. 1905. La Pavoni Ideale in production.2,3
    3. \n
  3. 1938. Gaggia patent application, reported by one museum only (hollow mark).4
    4. \n
  4. 1947. Gaggia’s tap patent filed in Italy (priority date).6
    5. \n
  5. 1948. Gaggia’s spring-lever machine.2,3
    6. \n
  6. 1956. Cimbali’s hydraulic group (Italian priority).9
    7. \n
  7. 1960. Valente’s pump and infusion-valve patents (Italian priorities).10,11
    8. \n
  8. 1961. Faema E61; Valente’s heat-exchanger patent.2,4,12,13
    9. \n
  9. 2017. Patents on a secondary boiler per group, stored pressure curves and PID control.7,14
    10. \n
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Milestones of the espresso machine at the year the patent record or two histories give; the hollow mark rests on one museum exhibition only. The axis is broken between 1966 and 2017.1,2,3,4,6,7,9,10,12,13,14
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\n\n\n\n## Reading the patent record\n\nPatent records give three different dates, and accounts often mix them. The priority date is the first filing, usually in Italy for these machines. The filing date is the application in the office that granted the document. The grant or publication date comes years later. Valente’s pump patent shows the spread: Italian priority 8 October 1960, US filing 4 October 1961, US grant 28 January 1964.10 Gaggia’s Austrian patent claims an Italian priority of 8 August 1947 but was published only in 1954.6\n\nCoffearium dates each milestone by the earliest date in the record consulted and names which date it is. Where only a museum or a single historian gives a date, the entry says so and lists it in Contested. Patents are evidence of how a machine was built and when it was filed. They are not evidence that the machine was sold, or that it worked well.\n\n## Patent and source record\n\n| Milestone | Office and number | Inventor or applicant | Priority / filing | Grant / publication | What the record describes | Source |\n|---|---|---|---|---|---|---|\n| Single-cup steam machine | US 726,793 | Luigi Bezzera, assigned to Desiderio Pavoni | Filed 10 Jun 1902 | Granted 28 Apr 1903 | Boiler with heating chambers, delivery cock, bell, perforated diaphragm, filter cup | 1 |\n| Tap for espresso machines | CH 262232 A | Giovanni Achille Gaggia | Not given here | Not given here | Lever-type machine, piston moved by a lever and pushed by a spring (as described in a 2017 patent) | 5,7 |\n| Tap for espresso machines | AT 179620 B | Giovanni Achille Gaggia | Italian priority 8 Aug 1947; filed 20 Mar 1950 | Published 25 Sep 1954 | Bibliographic record only | 6 |\n| Hydraulic group | US 2,878,747 | Vittorio Cimbali, Officine Cimbali | Italian priority 7 Apr 1956; filed 7 Sep 1956 | Granted 24 Mar 1959 | Mains water pressure on a servo piston drives the brewing piston | 9 |\n| Pump machine | US 3,119,322 | Ernesto Valente | Italian priority 8 Oct 1960; filed 4 Oct 1961 | Granted 28 Jan 1964 | Motor-driven pump run only when pressure is needed | 10 |\n| Infusion valve | US 3,230,974 | Ernesto Valente | Italian priority 24 Sep 1960; filed 25 Sep 1961 | Granted 25 Jan 1966 | Valve in the group opening at 1.5 atm, delaying the flow | 11 |\n| Heat exchanger and thermosiphon | AT 237214 B | Carlo Ernesto Valente | Italian priority 28 Nov 1961; filed 26 Nov 1962 | Published 10 Dec 1964 | Tube heat exchanger in the boiler, thermosiphon to the group, centrifugal pump preferred, soaking phase | 12 |\n| Secondary boiler per group; stored pressure curves | EP 3 653 086 A1 | Carimali S.p.A. | Priority 18 Jul 2017 | Published 20 May 2020 | Small boiler for each group; replayed pressure curves | 7 |\n| PID temperature control | US 11,517,143 B2 | La Marzocco S.r.l. | Priority 24 Mar 2017 | Granted 6 Dec 2022 | PID controller for the coffee boiler | 14 |\n\n| Milestone | Date | Evidence | Source |\n|---|---|---|---|\n| La Pavoni Ideale enters production | 1905 | Historian and museum exhibition agree | 2,3 |\n| Gaggia’s first patent application | 1938 | One museum exhibition; not confirmed | 4 |\n| Gaggia spring-lever machine | 1948 | Historian and museum exhibition agree | 2,3 |\n| Faema E61 | 1961 | Two museum exhibitions and a historian agree | 2,4,13 |\n\n## How pressure was decoupled from temperature\n\nEach design answers one constraint. In a saturated-steam boiler, steam sits over boiling water, and its pressure follows the temperature.7 According to the 2017 patent, keeping the water below boiling to avoid a burnt taste therefore capped the pressure, so the extraction pressure was a compromise.7\n\nA spring stores the barista’s work and releases it on the piston, so the pressure no longer depends on the boiler.7,8 But a spring pushes less as it extends. In the 2013 comparison, the lever machine’s pressure fell from 8 to 2 bar during the shot, and its temperature dropped about 10 °C.8 The pump machine with a heat exchanger held its pressure and a fairly constant temperature.8 The authors of that study attributed most of the difference in extraction to temperature.8\n\nThe hydraulic group replaced the spring with mains pressure. In Cimbali’s patent, the difference in diameter between a larger servo piston and the brewing piston mainly sets the pressure on the coffee.9 The pump made pressure independent of both the barista and the water main.10 The heat exchanger then let fresh water be heated on demand without drawing on the boiler water.12,13 In Valente’s 1961 patent, the small volume of each circuit and the circulation of the hot water keep the water from standing.12\n\n**Pre-infusion in the record.** Wetting the coffee at low pressure appears early in the patents. Valente’s 1960 valve delays the flow until 1.5 atm, and his 1961 patent describes a soaking phase.11,12 The 2017 patent notes that lever and hydraulic groups did this automatically, while pump machines needed a dedicated device.7 How pre-infusion is used is covered in the espresso machine entry.\n\n## Documented, claimed and retold\n\nCoffearium sorts the claims into three levels, as in the coffeehouse history. **Documented** means a patent record or two independent histories: Bezzera’s 1902 filing, the 1905 Ideale, Gaggia’s 1947 filing and 1948 machine, Cimbali’s 1956 priority, Valente’s 1960–1961 patents and the 1961 E61.1,2,3,6,9,10,12,13 **Claimed** means a date from one source only, such as Gaggia’s 1938 application and the 1901 date for Bezzera.2,4 **Retold** means firsts that change from one account to the next.\n\nThe best-known disputed first is not dated here. Accounts of an earlier steam machine patented by Angelo Moriondo could not be checked against a patent record or a historian’s text consulted for this entry. The entry therefore gives no date or description for it. The same holds for popular firsts after 1961, such as the first machine with a separate brew boiler. A 2002 magazine timeline calls Valente’s 1961 design the archetype of the modern machine, in line with the design museum.4,15\n\n## Open questions\n\n- **Moriondo’s patent.** No Italian patent record for it was consulted; the claim is neither confirmed nor rejected here.\n- **Bezzera’s Italian patent.** A museum dates his patent to 1901; only the US record of 1902–1903 was consulted.1,2\n- **Gaggia’s 1938 application.** Reported by one design museum; the patent record was not found.4\n- **Which patents protect the E61.** The Valente patents of 1960–1961 match the E61 as historians describe it, but no source consulted links them.10,11,12,13\n- **Firsts after 1961.** No patent record consulted dates the first rotary-pump, separate-boiler or PID-controlled machine; the 2017 patents are examples, not origins.7,14\n\n## Key studies\n\n
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Bezzera, 1903 – Coffee-making machine. A US patent for a boiler-fed bar machine with a delivery cock, a bell and a perforated diaphragm over a cup of coffee. Its point is service: each cup is prepared separately from fresh coffee instead of by the batch.

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US Patent 726,793 · patents.google.com/patent/US726793

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Valente, 1964 – Kaffeemaschine. An Austrian patent for a machine with a tube heat exchanger in the boiler, a motor-driven pump and thermosiphon circulation through the group between shots. It also describes a soaking phase before dispensing.

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Austrian Patent AT 237214 B · patents.google.com/patent/AT237214B

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Caprioli et al., 2013 – Pump versus lever. Logged pressure and temperature during shots on a pump machine with a heat exchanger and on a spring-lever machine. The lever machine’s pressure and temperature fell during the shot, and it extracted fewer chlorogenic acids.

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Journal of Food Research 2(3), 55–64 · doi:10.5539/jfr.v2n3p55

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Morris, 2017 – We consumers: tastes, rituals and waves. A historian places the La Pavoni Ideale of 1905 and Gaggia’s lever machine of 1948 in the history of Italian bars. He links the lever’s higher pressure to crema and to a new gap between coffee at the bar and at home.

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In: Folmer (ed.), The Craft and Science of Coffee, ch. 19 · doi:10.1016/B978-0-12-803520-7.00019-0

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