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Moka pot

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(Redirected from Moka (coffee pot))
Not to be confused with Caffè mocha or Mocha coffee bean.
Moka pot
Bialetti Moka Express
IndustryCoffee in Italy
ApplicationCoffee preparation
InventorSamuel Parker
Invented1833
ManufacturersBialetti

The moka pot[1][2] is a stove-top or electric coffee maker that brews coffee by passing hot water driven by vapor pressure and heat-driven gas expansion through ground coffee. Named after the Yemeni city of Mocha, it was popularized by Italian aluminum vendor Alfonso Bialetti and his son Renato starting from 1933.[3][4][5] It quickly became one of the staples of Italian culture. Bialetti Industries continues to produce the original model under the trade name "Moka Express".

Spreading from Italy, the moka pot is today most commonly used in Europe, Latin America, and Australia. It has become an iconic design, displayed in modern industrial art and design museums including the Wolfsonian-FIU, the Cooper–Hewitt, National Design Museum, the Design Museum,[6] the London Science Museum, The Smithsonian and the Museum of Modern Art.[7] Moka pots come in different sizes, making from one to eighteen 50 ml (2 imp fl oz; 2 US fl oz) servings.[8]

The original design and many current models are made from aluminium with Bakelite handles, though they are sometimes made out of stainless steel or other alloys. Some designs feature an upper half made of heat-resistant glass.

Use

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The bottom chamber (A) contains water. When heated, steam pressure pushes the water through a basket containing ground coffee (B) into the collecting chamber (C).

Moka pots are used over a source of heat, typically a flame or electric range. Stainless steel pots, but not aluminium, can be used with induction cooking.

There are three major components in a typical moka pot:

  1. The lower chamber or lower vessel, also known as the boiler, which is fitted with a safety valve to prevent over-pressurization
  2. The filter funnel or basket, which compresses an annular rubber gasket when the moka pot is assembled and seals against an upper filter disc
  3. The upper chamber or upper vessel, also known as the collector, which is where the coffee is deposited during the brewing process

The moka pot is assembled first by inserting the filter funnel into the lower chamber, then threading the upper chamber onto the lower chamber, which compresses the rubber gasket against the lip of the filter funnel to seal the lower chamber. Generally, the upper filter disc is retained on the bottom of the upper chamber by the rubber gasket, which acts as a flexible internal circlip; this filter disc prevents coffee grounds from moving up the spout of the upper chamber.

Preparation

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The boiler (marked A in the diagram) is filled with water to an etched line (or slightly below the safety release valve). While at-home makers generally do not preheat the water used, it can expedite the brewing process in commercial settings.[9][10] The metal filter funnel (B) is inserted. Finely ground coffee is added to the filter. How tightly the coffee is packed impacts how quickly the coffee extracts and the strength of the brew.[11] The collector (C) is then attached and the pot is heated, so that the water boils.

  • Stages of brewing coffee with a moka pot
  • Funnel with ground coffee
    Funnel with ground coffee
  • Mid-brew, showing brewed coffee in the process of being transported through the spout
    Mid-brew, showing brewed coffee in the process of being transported through the spout
  • Layer of crema developing
    Layer of crema developing

Brewing

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How the moka pot works
X-ray video of a moka pot in use

The heating of the boiler (A) leads to a gradual increase of the pressure due to both the expansion of the enclosed air and the raised vapor pressure of the increasingly heated water. When pressure becomes high enough to force the water up the funnel through the coffee grinds, brewed coffee rises through the vertical spout and pours into the upper chamber (C).

When the lower chamber is almost empty, bubbles of steam mix with the upstreaming water, producing a characteristic gurgling noise—a signal that brewing should be stopped. Navarini et al. call this the "strombolian" phase of brewing, which allows a mixture of highly heated steam and water to pass through the coffee, which leads to rapid overextraction and introduction of undesirable flavors.[11]

Unlike a standard percolator, the moka pot never sends brewed coffee back through the coffee grounds.

A number of physics papers were written between 2001 and 2009 utilizing the ideal gas and Darcy's laws, along with the temperature-dependent vapor pressure of water, to explain the moka pot's brewing process.[12]

Moka coffee characteristics

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Brewed coffee flavor, including that of a moka pot depends greatly on bean variety, roast level, fineness of grind, water profile, and the level of heat used.

Moka pots are sometimes referred to as stove-top espresso makers. However, a typical moka coffee is extracted at relatively low pressures of 1 to 2 bar (100 to 200 kPa),[11] while standards for espresso coffee specify a pressure of 9 bar (900 kPa). Therefore, moka coffee is not considered to be an espresso.[13][14] Typically, the moka pot uses a ratio of coffee to water, by mass, of approximately 1:10, resulting in a brew with approximately 3–4% dissolved solids. In comparison, espresso is "stronger" with 9–10% dissolved solids, and drip-brewed coffee is "weaker" with approximately 2% dissolved solids.[15]

Maintenance

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Disassembled Bialetti Moka Express, showing (bottom to top) the bottom chamber (boiler) with safety valve, funnel filter, seal, upper filter disc, and upper chamber (collector).

Moka pots require periodic replacement of the rubber seal, a scouring of its removable filter, and a check that the safety release valve is not blocked. All parts of the pot should be scrubbed by hand using a mild detergent, as aluminium moka pots are not dishwasher safe.[16][17][18]

Aluminium migration

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The potential for toxic amounts of aluminium migration being created by brewing an acidic beverage in an aluminium pot have been scientifically investigated, and determined to be "negligible" – falling below 1% of recommended total weekly intake level once a new pot has been used.[19] Following the pot's stabilization at below 1% with regular use, migration rose to a maximum observed level of just under 4% after a dishwasher cleaning, resulting in dishwasher use being strongly discouraged.

History and variants

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  • Steam pressure-driven coffee machine (1868)
    Steam pressure-driven coffee machine (1868)
  • Coffee machine c. 1900 similar to Parker's Steam Fountain
    Coffee machine c. 1900 similar to Parker's Steam Fountain
  • Several models of Bialetti moka pot
    Several models of Bialetti moka pot
  • Moka 2 Cup Coffee Fountain[20]
    Moka 2 Cup Coffee Fountain[20]

The principle of brewing coffee by using steam to force heated water through a bed of roasted, ground beans dates back to at least 1818, according to a patent published by Elard Römershausen for a very large machine.[21] A more portable machine incorporating the same basic principle was designed by Louis Bernard Rabaut in 1822, according to drawings submitted to the French Academy of Sciences,[22] followed by similar designs by Andre Caseneuve (1824), Edouard Doublet, and Pierre-Isidore Rouen (1833).[21]

Samuel Parker, a coppersmith from Middlesex, was granted a patent on January 11, 1833, for a tabletop machine which used a brewing method that sends self-pressurized hot water from a sealed vessel vertically through a bed of packed coffee grounds into a collector, as an improvement on the coffee percolator.[23] Parker's "Steam Fountain" was sold starting in the 1840s, featuring a cylindrical body with two concentric vessels: an inner boiler and outer collector, topped by a glass dome which served to redirect the brewed coffee into the collector.[24] It later became known as the "Vienna Incomparable". Similar steam pressure-driven devices were invented in Paris by Alexandre Lebrun (1838) and in Berlin by H. Eicke (1878).[24]

Alfonso Bialetti popularized the machine for home use, initially marketing the Moka Express starting in 1933,[25] but relatively few were sold until his son Renato embarked on a major marketing campaign after the latter took over the family business in the 1940s, including the commissioning of the company's iconic mascot, l'omino con i baffi, in 1952.[3] Bialetti Industries applied for a patent in 1946 describing an apparatus which uses the same brewing method but arranges the vessels side by side, rather than stacking them vertically.[26]

Among the variations to the moka pot design that have been introduced since the 1930s are those that integrate an electric heating element in the boiler,[27] expedite brew time,[28] create milk froth,[29] and allow microwave brewing.

To expedite brewing, a weighted valve called Cremavent has been added as a pressure regulator on top of the nozzle that allows pressure to build up inside the water tank in a manner similar to a pressure cooker. As pressure builds up more quickly in this method (since there is much less leakage of vapour) compared to the standard moka pot, it reaches the level required for water to rise through the ground coffee in a shorter time. The result is coffee brewed at a higher pressure and temperature than the standard pot, making it more similar to espresso and therefore with more visible crema.[30]

Another variation (the Bialetti Mukka Express) allows for milk to be frothed and mixed with the coffee during brewing.[31]

Pot sizes

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Moka pots are sold in various sizes based on the approximate number of espresso-sized cups they produce, with each cup measuring 50 ml (2 imp fl oz; 2 US fl oz). The following table lists sizes for some popular Bialetti Moka pots:

Bialetti Moka pot sizes
Cup size "Moka Express"[32] "Venus"[33] / "Musa" / "Kitty"
volume height base volume height base
1 60 ml (2 US fl oz) 135 mm (5+1⁄4 in) 70 mm (2+3⁄4 in) —
2 90 ml (3 US fl oz) 145 mm (5+3⁄4 in) 80 mm (3+1⁄4 in) 85 ml (3 US fl oz) 140 mm (5+1⁄2 in) 80 mm (3+1⁄4 in)
3 130 ml (4+1⁄2 US fl oz) 160 mm (6+1⁄4 in) 90 mm (3+1⁄2 in) —
4 185 ml (6+1⁄2 US fl oz) 180 mm (7 in) 95 mm (3+3⁄4 in) 170 ml (5+1⁄2 US fl oz) 170 mm (6+3⁄4 in) 95 mm (3+3⁄4 in)
6 250 ml (8+1⁄2 US fl oz) 215 mm (8+1⁄2 in) 105 mm (4+1⁄4 in) 235 ml (8 US fl oz) 200 mm (7+3⁄4 in) 105 mm (4+1⁄8 in)
9 410 ml (14 US fl oz) 245 mm (9+3⁄4 in) 115 mm (4+1⁄2 in) —
10 — 460 ml (15+1⁄2 US fl oz) 230 mm (9 in) 130 mm (5+1⁄8 in)
12 595 ml (20 US fl oz) 285 mm (11+1⁄4 in) 135 mm (5+1⁄4 in) —
18 800 ml (27 US fl oz) 320 mm (12+1⁄2 in) 135 mm (5+1⁄4 in) —

See also

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References

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  1. ^ "Why We Love the Bialetti Moka Pot". The New York Times. 26 January 2021. Archived from the original on 22 June 2023. Retrieved 22 June 2023.
  2. ^ "Bialetti Brikka vs. Bialetti Moka Express". 101 Coffee Machines .info. Archived from the original on 22 June 2023. Retrieved 22 June 2023.
  3. ^ a b Purtill, Corinne (18 February 2016). "Italy's coffee pot king was buried in the appliance that made him famous". qz.com. Archived from the original on 9 October 2024. Retrieved 14 May 2023.
  4. ^ "Bialetti Technical Description". fmartinezport.commons.gc.cuny.edu. Archived from the original on 9 October 2024. Retrieved 14 May 2023.
  5. ^ "Who Made That Moka Express". The New York Times. Archived from the original on 9 October 2024. Retrieved 14 May 2023.
  6. ^ Greenbaum, Hilary (1 September 2011). "Who Made That Moka Express?". The 6th Floor Blog. Archived from the original on 7 August 2021. Retrieved 7 August 2021.
  7. ^ Wilson, Mark (9 April 2019). "The world's most famous coffee pot gets a redesign". Fast Company. Archived from the original on 23 October 2022. Retrieved 10 October 2022.
  8. ^ "Moka Express factsheet" (PDF). Bialetti. Archived from the original (PDF) on 14 December 2010. Retrieved 1 March 2009.
  9. ^ Hoffmann, James (2020). The World Atlas of Coffee. Firefly Books. p. 91. ISBN 978-0-2281-0094-2.
  10. ^ Stephenson, Tristan (2019). The Curious Barista's Guide to Coffee. New York: Ryland Peters & Small. p. 132. ISBN 978-1-78879-083-3.
  11. ^ a b c Navarini, L.; Nobile, E.; Pinto, F.; Scheri, A.; Suggi-Liverani, F. (April 2009). "Experimental investigation of steam pressure coffee extraction in a stove-top coffee maker" (PDF). Applied Thermal Engineering. 29 (5–6): 998–1004. doi:10.1016/j.applthermaleng.2008.05.014. S2CID 110656959. Archived (PDF) from the original on 9 October 2024. Retrieved 7 August 2021.
  12. ^ *A. Varlamov and G. Balestrino, La fisica di un buon caffè Archived 9 October 2024 at the Wayback Machine, Il Nuovo Saggiatore: Bollettino della Società Italiana di Fisica 17(3-4) Archived 23 March 2023 at the Wayback Machine, 59–66 (2001)
  13. ^ "Espresso Italiano Certificato" (PDF). Istituto Nazionale Espresso Italiano. Archived from the original (PDF) on 26 July 2011. Retrieved 30 January 2011.
  14. ^ "Espresso and classic drink Wiki". Archived from the original on 7 July 2011. Retrieved 30 January 2011.
  15. ^ Raub, Jesse (30 January 2025). "I Tested 11 Moka Pots—the Best Were From the Same Iconic Brand". Serious Eats. Retrieved 26 February 2025.
  16. ^ "Tips and Care". Archived from the original on 9 October 2024. Retrieved 27 November 2020. bialetti.co.nz
  17. ^ "How to Clean a Moka Pot". thekitchn.com Running the pot through the dishwasher generally results in corrosion and oxidation of the protective oxidized layer of aluminium, leaving freshly exposed aluminium to react with the air, creating a dirty, reactive, and blackened surface.
  18. ^ Stahl, Thorsten; et al. (12 April 2017). "Migration of aluminum from food contact materials to food—a health risk for consumers?". Environmental Sciences Europe. 29 (18): 18. doi:10.1186/s12302-017-0118-9. PMC 5388725. PMID 28458988. While not producing unsafe levels, brewing with the pot after dishwasher usage results in a larger aluminium content leaching into the coffee.
  19. ^ Stahl, Thorsten; et al. (12 April 2017). "Migration of aluminum from food contact materials to food—a health risk for consumers?". Environmental Sciences Europe. 29 (18): 18. doi:10.1186/s12302-017-0118-9. PMC 5388725. PMID 28458988. [H]uman inner aluminum exposure through the proper use of aluminum moka pots is negligible. Even under the worst-case scenario of washing the moka pots in a dishwasher, the uptake amounts to only 4% of TWI. The manufacturers expressly warn not to clean the aluminum moka pots in the dishwasher. Summary: An initially low level of aluminium migration (of under 3% recommended total weekly intake (TWI)) occurs after the first use of a new pot, after which the level stabilizes below 1% TWI, decreasing with each observed use; migration after dishwasher cleaning increases to a maximum observed level of just under 4%, and thus dishwasher cleaning is strongly discouraged.
  20. ^ "Fontanella Argento per una tazzina". Sant'Eustachio il Caffè (in Italian). Archived from the original on 9 October 2024. Retrieved 22 June 2023.
  21. ^ a b Delprat, Sebastien (27 October 2022). "Part 1 – Who really invented the first espresso machine?". Barista Hustle. Retrieved 26 February 2025.
  22. ^ Prikhodko, Anastasia (3 June 2021). "A History of the Espresso Machine". Coffee Magazine. Retrieved 26 February 2025.
  23. ^ Titles of Patents of Invention, Chronologically Arranged From March 2, 1617 (14 James I.) to October 1, 1852 (16 Victoria), Part II: Nos. 4801 to 14,359, pages 785 to 1554. Queen's Printing Office. 1854. Retrieved 26 February 2025. No. 6362. A grant unto SAMUEL PARKER, of Argyle Street, Oxford Street, in the county of Middlesex, bronzist, of his invention of "certain improvements in apparatus for making extracts from coffee and other substances"; to hold, &tc; six months.
  24. ^ a b "Steam Pressure ('long' espresso)". Espresso made in Italy. Retrieved 26 February 2025.
  25. ^ Stephenson, Tristan (2015). "Other Brewing Methods: The Moka Pot". The Curious Barista's Guide to Coffee. Photographs by Addie Chinn. Ryland Peters & Small. pp. 117–119. ISBN 978-1-84975-563-4.
  26. ^ GB Patent 616773A, Soc. An. Fratelli Bialetti, "Percolator for Preparing Coffee or like Infusions", published January 26, 1949 
  27. ^ Preuss, Arne. Nicholas Marshall (ed.). "The Moka Pot Review: A Stovetop Portafilter?". Coffeeness. Retrieved 26 February 2025.
  28. ^ IT Patent 1171070B, Luigi de Ponti, "Apparecchio e procedimento per la preparazione di una bevanda calda di latte e infuso di caffe' con strato di shiuma (cappuccino)", published June 10, 1987, assigned to Alfonso Bialetti & Co. 
  29. ^ DE Patent 3404320A1, Luigi de Ponti, "Für den Gebrauch im Haushalt bestimmte Vorrichtung für die Herstellung von warmen Getränken und entsprechenden Kaffee-maschinen", published September 27, 1984, assigned to Alfonso Bialetti & C. S.p.A. 
  30. ^ Bien, Heather (21 October 2022). "Bialetti Brikka Review: Does the Brikka Produce Crema?". C'est Bien. Retrieved 26 February 2025. So, Does the Brikka Produce Crema?
     Yes! It's not going to be as rich or as thick as what you'll get from a standard espresso machine, but if you follow the tricks above, the Brikka does produce crema, in addition to a bold, deep flavor that can't be beat.
  31. ^ How to Use the Bialetti Mukka Express. Alternative Brewing. Archived from the original on 27 February 2023. Retrieved 8 July 2024 – via YouTube.
  32. ^ "Bialetti Moka Express". Bialetti New Zealand. Retrieved 25 February 2025.
  33. ^ "Bialetti Venus". Bialetti New Zealand. Retrieved 25 February 2025.

Further reading

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Media related to Moka pot at Wikimedia Commons

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