{ "id": "coffee-capsules", "url": "https://coffearium.org/entries/coffee-capsules/", "license": "CC-BY-4.0", "title": "Coffee capsules", "summary": "A coffee capsule is a sealed single dose of ground coffee that its machine pierces and brews under pressure. How a capsule opens and brews, what studies measured in the cup, and where the system came from.", "domain": "equipment", "kind": "Equipment", "stage": "brew", "topics": [ "equipment", "history" ], "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": [ "A capsule is a closed single dose of ground coffee; the machine pierces it and injects hot water, and in Nestlé’s patents the outlet opens under the water pressure.2,3,6", "In a Nestlé patent first filed in 1991, the outlet face presses onto raised pyramids in the capsule holder and tears there, letting the coffee out.4", "In a 2020 study of 43 Nespresso-system capsules, each held 4.97–6.17 g of coffee; brews of about 40 g reached 15.7–26% extraction yield.7", "The earliest Nestlé capsule patent consulted was filed in Switzerland on 17 December 1976 and names Eric Favre as inventor.1", "In 2014 the French competition authority made binding Nespresso’s commitment to tell makers of compatible capsules about machine changes in advance.6,14" ], "quickFacts": [ { "label": "What it is", "value": "Closed, single-dose container of ground coffee for one machine system" }, { "label": "Inlet", "value": "Pierced by the machine’s injection needle" }, { "label": "Outlet", "value": "Membrane that tears under water pressure (Nespresso-type patents)" }, { "label": "Coffee per capsule", "value": "4.97–6.17 g (43 capsules, 2020); 5–7 g in other studies" }, { "label": "Beverage", "value": "30 mL (2013 study); about 40 g (2020 study)" }, { "label": "Machine pressure stated", "value": "13–19 bar (as reported in three studies)" }, { "label": "Earliest patent consulted", "value": "CH 605293, filed 17 Dec 1976 (Nestlé)" } ], "aka": [ "Coffee capsule", "Capsule coffee", "Espresso capsule" ], "linkTerms": [ "coffee capsule", "capsule machine", "capsule machines", "capsule system", "capsule systems", "compatible capsules" ], "related": [ "how-capsules-are-made", "capsules-and-the-environment", "single-serve-beyond-capsules", "espresso", "espresso-machine", "reading-a-shot", "packaging", "extraction-variables", "extraction-yield-and-tds", "espresso-recipes-and-ratios", "degassing" ], "contested": [ "Brew ratio compared with barista espresso: a coffee science textbook chapter describes pressure and coffee-to-water ratio in capsule systems as comparable to those of a barista espresso.12 In the two studies consulted that report both dose and cup, the ratio was about 5.5 mL per gram of coffee in a 2013 study and 6.5–8.2 g per gram in a 2020 study (our calculation: cup divided by the mean coffee per capsule).7,8 Espresso ratios are compared in Espresso recipes and ratios.", "Year of one machine change: the French competition decision dates the ribs, hooks and grooves added to Nespresso machines to July 2010 (for one model) in one paragraph and to 2011 in another.6" ], "corrections": [ { "date": "2026-10-27T00:00:00.000Z", "change": "French competition decision described as a commitments decision; the four machine modifications are what the authority's investigation services found, with no fine or finding of infringement.", "reason": "The press release describes the practices only as liable to constitute an abuse and closes the case on commitments." }, { "date": "2026-10-27T00:00:00.000Z", "change": "Sensory scores attributed to three certified Q graders instead of a trained panel; fines described as going with longer brewing times rather than governing them.", "reason": "Methods and results of Eiermann et al. 2020 (consensus of three Q graders; fines explain part of the time variance)." }, { "date": "2026-10-27T00:00:00.000Z", "change": "Imaging study identified as Iperespresso-system capsules; open question on other systems and temperature wording corrected.", "reason": "Mo et al. 2023 used Iperespresso capsules and stated, not measured, the water temperature." }, { "date": "2026-10-27T00:00:00.000Z", "change": "Brew ratio recalculated per product from Table 1 (6.5–8.2 instead of 6.5–8.0 g per g) with its basis stated.", "reason": "Our calculation now uses each product's own brew mass." } ], "sources": [ { "id": "s1", "title": "CH 605293 A5 (family: US 4,136,202; DE 2752733; FR 2373999; GB 1561188)", "authors": "Favre, E. M. J. (inventor); Nestlé SA (assignee)", "year": 1978, "publisher": "Swiss patent, via Google Patents", "url": "https://patents.google.com/patent/CH605293A5/en", "tier": "A", "tierNote": "Patent record; A for the filing date, applicant, inventor and construction only, never for performance.", "quote": "Eric Marc Joseph Favre", "quotes": [], "scope": { "claim": "data", "context": "Patent register entry (inventor, applicant Nestlé SA, dates); filed in Switzerland 17 Dec 1976, published 29 Sep 1978; no English title, claims or description shown on the record consulted", "checked": "2026-10-27T00:00:00.000Z" }, "accessed": "2026-10-27T00:00:00.000Z" }, { "id": "s2", "title": "Capsule for beverage preparation (US 4,136,202)", "authors": "Favre, E. (inventor); Société d’Assistance Technique pour Produits Nestlé SA (assignee)", "year": 1979, "publisher": "United States patent, via Google Patents", "url": "https://patents.google.com/patent/US4136202A/en", "tier": "A", "tierNote": "Patent; A for construction and dates only, never for performance.", "quote": "This pressure initially causes the membrane 5 to expand and finally to break along the line of weakness 7.", "quotes": [ { "text": "its vertex is perforated by an injecting member 12 of the apparatus", "for": "Piercing of the closed top" }, { "text": "sheet aluminium between 60 and 110μ thick, preferably 80μ", "for": "Body material" }, { "text": "a sieve composed of polypropylene with orifices of between 40 and 60μ", "for": "Filter inside the capsule" }, { "text": "The pressure may be relatively high and may attain about 16 bar.", "for": "Water pressure described in the patent" }, { "text": "Finally the drink flows directly through the aperture 8 into the receiving vessel.", "for": "Outflow" } ], "scope": { "claim": "description", "context": "Patent for an aluminium capsule shaped as a truncated cone, closed by a membrane with a line of weakness; filed 7 Dec 1977, granted 23 Jan 1979, priority 17 Dec 1976", "checked": "2026-10-27T00:00:00.000Z" }, "accessed": "2026-10-27T00:00:00.000Z" }, { "id": "s3", "title": "Closed cartridge for making a beverage (EP 0 512 468 B1)", "authors": "Fond, O. (inventor); Société des Produits Nestlé SA (assignee)", "year": 1997, "publisher": "European patent, via Google Patents", "url": "https://patents.google.com/patent/EP0512468B1/en", "tier": "A", "tierNote": "Patent; A for construction and dates only. The expiry date on the record is the register's estimate, not a legal finding.", "quote": "intended to be torn solely under the effect of the pressure of the extraction fluid", "quotes": [], "scope": { "claim": "description", "context": "Patent for a closed cartridge whose outlet face tears under the pressure of the brewing water; priority 10 May 1991, filed 4 May 1992, granted 29 Jan 1997", "checked": "2026-10-27T00:00:00.000Z" }, "accessed": "2026-10-27T00:00:00.000Z" }, { "id": "s4", "title": "Method of producing beverages using sealed cartridges and apparatus for carrying out this method (EP 0 512 470 B1)", "authors": "Fond, O.; Lavanchy, G.; Yoakim, A. (inventors); Société des Produits Nestlé SA (assignee)", "year": 1996, "publisher": "European patent, via Google Patents", "url": "https://patents.google.com/patent/EP0512470B1/en", "tier": "A", "tierNote": "Patent; A for construction and dates only, never for performance. The expiry date on the record is the register's estimate.", "quote": "The coffee extract manages to pass between the torn and deformed parts of the extraction face of the cartridge", "quotes": [ { "text": "against a raised surface of the cartridge holder comprising raised elements", "for": "Relief plate in the capsule holder" }, { "text": "under a pressure of 1 to 20 bars", "for": "Pressure range in the patent" } ], "scope": { "claim": "description", "context": "Patent for the brewing method and holder with raised elements (truncated pyramids); priority 8 May 1991, filed 5 May 1992, granted 24 Apr 1996; machine translation of the French text", "checked": "2026-10-27T00:00:00.000Z" }, "accessed": "2026-10-27T00:00:00.000Z" }, { "id": "s5", "title": "Beverage filter cartridge (US 5,325,765)", "authors": "Sylvan, J. E.; Dragone, P. B. (inventors); Keurig Inc. (assignee)", "year": 1994, "publisher": "United States patent, via Google Patents", "url": "https://patents.google.com/patent/US5325765A/en", "tier": "A", "tierNote": "Patent; A for construction and dates only, never for performance.", "quote": "A second penetrator or needle 74 is pushed through the bottom 76 of base 12", "quotes": [ { "text": "a penetrator or needle 70 which penetrates domed cover 14 to provide pressurized hot water", "for": "Inlet needle through the lid" } ], "scope": { "claim": "description", "context": "Patent for a cartridge with an impermeable base, an internal filter element and a pierceable cover; filed 16 Sep 1992, granted 5 Jul 1994", "checked": "2026-10-27T00:00:00.000Z" }, "accessed": "2026-10-27T00:00:00.000Z" }, { "id": "s6", "title": "Décision n° 14-D-09 du 4 septembre 2014 relative à des pratiques mises en œuvre par les sociétés Nestlé, Nestec, Nestlé Nespresso, Nespresso France et Nestlé Entreprises dans le secteur de la fabrication des machines à café expresso", "authors": "Autorité de la concurrence", "year": 2014, "publisher": "Autorité de la concurrence (France)", "url": "https://www.autoritedelaconcurrence.fr/sites/default/files/commitments/14d09.pdf", "tier": "A", "quote": "la machine assure le perçage de la capsule et le passage de l'eau au travers de la mouture", "quotes": [ { "text": "Nestlé Nespresso, Nestec et Nestlé sont situées en Suisse", "for": "Seat of the companies" }, { "text": "Nespresso a créé et développé la technologie de l'expresso domestique préparé à partir de café portionné", "for": "Origin of the technology" }, { "text": "Depuis le 7 avril 2010, DEMB vend en France des capsules compatibles avec les machines Nespresso", "for": "First compatible capsules in France" }, { "text": "Nespresso a décidé, en 2007, de transférer de la machine à la capsule le joint", "for": "Seal moved to the capsule" }, { "text": "la plaque pyramidale de l'unité d'extraction de café", "for": "Pyramid plate" }, { "text": "Au cours de l'année 2013, Nespresso a introduit un nouveau système de perforation", "for": "New piercing system" } ], "scope": { "claim": "finding", "context": "Commitments decision of a national competition authority (preliminary assessment, no finding of infringement); facts on machines, capsules and compatible capsule makers in France, 2007–2014", "checked": "2026-10-27T00:00:00.000Z" }, "accessed": "2026-10-27T00:00:00.000Z" }, { "id": "s7", "title": "Extraction of single serve coffee capsules: linking properties of ground coffee to extraction dynamics and cup quality", "authors": "Eiermann, A.; Smrke, S.; Guélat, L.-M.; Wellinger, M.; Rahn, A.; Yeretzian, C.", "year": 2020, "publisher": "Scientific Reports 10, 17079", "url": "https://www.nature.com/articles/s41598-020-74138-1", "doi": "10.1038/s41598-020-74138-1", "tier": "A", "quote": "The study was conducted on 43 Nespresso and Nespresso-compatible capsules of the same geometry, from all of which the coffee was extracted on the same machine.", "quotes": [ { "text": "The resulting brew weight was 40.1 ± 0.3 g (mean ± s.d), with all brews between 39.6 and 40.7 g.", "for": "Beverage mass" }, { "text": "covering a range between 10 and 41 s", "for": "Extraction times" }, { "text": "The capsule coffee grinds show a wide spread in the amount (proportion) of fines, over the range from 6 to 16% of volume.", "for": "Share of fines" }, { "text": "No correlation of the capsule pressure with the extraction dynamics was observed.", "for": "Internal capsule pressure" }, { "text": "It was demonstrated that the most efficient way to increase total dissolved solids in the brew is to use more coffee for extraction, and/or to grind the coffee more finely.", "for": "Strength levers" }, { "text": "The coffee sensory quality in the cup was not correlated to the technical variables of the grounds.", "for": "Sensory quality" } ], "scope": { "claim": "finding", "context": "43 capsule coffees of one geometry (Nespresso and compatibles), one capsule machine, brews stopped at 40 g; coffee mass, TDS and extraction yield from Table 1 (n = 3 per product); Switzerland", "checked": "2026-10-27T00:00:00.000Z" }, "accessed": "2026-10-27T00:00:00.000Z" }, { "id": "s8", "title": "Comparison of nine common coffee extraction methods: instrumental and sensory analysis", "authors": "Gloess, A. N.; Schönbächler, B.; Klopprogge, B.; D’Ambrosio, L.; Chatelain, K.; Bongartz, A.; Strittmatter, A.; Rast, M.; Yeretzian, C.", "year": 2013, "publisher": "European Food Research and Technology 236, 607–627", "url": "https://digitalcollection.zhaw.ch/bitstream/11475/4251/2/2013_Gloess-etal_Comparison-of-nine-common-coffee-extraction-methods.pdf", "doi": "10.1007/s00217-013-1917-x", "tier": "A", "quote": "The espressi DE, SE and NE had a content of total solids of above 4%, which is typical for an espresso.", "quotes": [ { "text": "The single-serve capsule system was the extraction with the highest quantity of the darkest crema.", "for": "Crema of the capsule brew" } ], "scope": { "claim": "finding", "context": "Nine brewing methods compared in one laboratory; the capsule method used a different, commercial coffee (one Nespresso product, 10 capsules, about 30 mL each); dose, time and the manufacturer's pressure from Table 1; Switzerland", "checked": "2026-10-27T00:00:00.000Z" }, "accessed": "2026-10-27T00:00:00.000Z" }, { "id": "s9", "title": "Foam Characteristics and Sensory Analysis of Arabica Coffee, Extracted by Espresso Capsule and Moka Methods", "authors": "Lomolino, G.; Dal Zotto, V.; Zannoni, S.; De Iseppi, A.", "year": 2022, "publisher": "Beverages 8(2), 28", "url": "https://www.mdpi.com/2306-5710/8/2/28/htm", "doi": "10.3390/beverages8020028", "tier": "A", "quote": "For each coffee evaluated, the thickness of the crema was measured in a 25 mL graduated cylinder after extraction.", "quotes": [ { "text": "Coffee content in the capsules is 5 g.", "for": "Dose, Nespresso-compatible capsules" }, { "text": "The coffee content in the capsules is 7 g.", "for": "Dose, Dolce Gusto-compatible capsules" }, { "text": "High pressures ensure greater stability, and this is also confirmed by the macroscopic and microscopic analysis.", "for": "Crema stability by extraction pressure" } ], "scope": { "claim": "finding", "context": "Capsule espresso from two arabica origins (Guatemala, Brazil), 5 g at 19 bar and 7 g at 15 bar (machine pressures as stated); crema height each minute for 10 min, bubble size by microscopy, trained sensory panel; Italy", "checked": "2026-10-27T00:00:00.000Z" }, "accessed": "2026-10-27T00:00:00.000Z" }, { "id": "s10", "title": "Exploring the link between coffee matrix microstructure and flow properties using combined X-ray microtomography and smoothed particle hydrodynamics simulations", "authors": "Mo, C.; Johnston, R.; Navarini, L.; Suggi Liverani, F.; Ellero, M.", "year": 2023, "publisher": "Scientific Reports 13, 16374", "url": "https://cronfa.swansea.ac.uk/Record/cronfa64681/Download/64681__28732__cf1888c5dbe64008b6a6e7afcc1c36ad.pdf", "doi": "10.1038/s41598-023-42380-y", "tier": "A", "quote": "a decreasing porosity profile (from the bottom-outlet to the top-inlet) always develops after extraction.", "quotes": [ { "text": "Each capsule contains 6.7±0.1 gram of coffee powder.", "for": "Dose per capsule" }, { "text": "after extraction the coffee cakes become less porous, the porosity decreases significantly.", "for": "Bed after extraction" }, { "text": "since the water is infused from the top to the bottom.", "for": "Flow direction" } ], "scope": { "claim": "finding", "context": "X-ray microtomography of coffee beds in Iperespresso-system capsules before and after extraction (stated conditions 97 ± 3 °C, 13 ± 1 bar), with flow simulations; one arabica blend, medium and dark roast", "checked": "2026-10-27T00:00:00.000Z" }, "accessed": "2026-10-27T00:00:00.000Z" }, { "id": "s11", "title": "Comparison of espresso coffee brewing techniques", "authors": "Parenti, A.; Guerrini, L.; Masella, P.; Spinelli, S.; Calamai, L.; Spugnoli, P.", "year": 2014, "publisher": "Journal of Food Engineering 121, 112–117", "url": "https://flore.unifi.it/handle/2158/893002", "doi": "10.1016/j.jfoodeng.2013.08.031", "tier": "A", "quote": "Furthermore, in terms of product reproducibility, the best results are provided by the two capsule systems.", "quotes": [ { "text": "the three different techniques can be distinguished by a principal component analysis", "for": "Capsule and bar espresso differ" } ], "abstractOnly": true, "scope": { "claim": "finding", "context": "Two capsule systems and a bar machine, same roasted coffee, water and settings; nine espressos analysed; physico-chemical and aroma analysis; abstract consulted; Italy", "checked": "2026-10-27T00:00:00.000Z" }, "accessed": "2026-10-27T00:00:00.000Z" }, { "id": "s12", "title": "The Brew – Extracting for Excellence", "authors": "Mestdagh, F.; Glabasnia, A.; Giuliano, P.", "year": 2017, "publisher": "In: Folmer, B. (ed.), The Craft and Science of Coffee, Academic Press, ch. 15, pp. 355–380", "url": "https://doi.org/10.1016/B978-0-12-803520-7.00015-3", "doi": "10.1016/B978-0-12-803520-7.00015-3", "tier": "B", "tierNote": "Chapter in a recognised textbook; Folmer chapters count as one Tier B source and carry no number alone in this entry.", "quote": "Almost all parameters are fixed allowing also very unexperienced users to obtain a very good cup of coffee.", "quotes": [ { "text": "A given pump can deliver the highest pressures at the lowest flow rates.", "for": "Pump pressure and flow" }, { "text": "The coffee bed properties (permeability) will decide on the actual operating pressure and the corresponding flow rate across the bed", "for": "Bed decides the operating pressure" }, { "text": "Pressure and coffee/water ratio are comparable to those of a barista type espresso preparation resulting also in a strong coffee with good crema on top of it.", "for": "Capsule brew compared with barista espresso" } ], "scope": { "claim": "description", "context": "Textbook chapter on brewing; general statement on single-serve espresso systems, no data", "checked": "2026-10-27T00:00:00.000Z" }, "accessed": "2026-10-27T00:00:00.000Z" }, { "id": "s13", "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. 457–488 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", "tierNote": "Chapter by a university historian of coffee in a recognised textbook; Folmer chapters count as one Tier B source; no number in this entry rests on it alone.", "quote": "Other roasters have either introduced their own systems, or offered Nespresso compatible capsules, usually seeking to undercut Nespresso itself.", "quotes": [ { "text": "The expiry of many of the patents that protected Nespresso’s proprietary systems since 2012", "for": "Patent expiry" } ], "scope": { "claim": "description", "context": "History chapter on coffee consumption; capsule systems as a market development", "checked": "2026-10-27T00:00:00.000Z" }, "accessed": "2026-10-27T00:00:00.000Z" }, { "id": "s14", "title": "Single-portion Espresso Coffee Machines (press release on decision 14-D-09)", "authors": "Autorité de la concurrence", "year": 2014, "publisher": "Autorité de la concurrence (France)", "url": "https://www.autoritedelaconcurrence.fr/en/entityprint/pdf/node/531", "tier": "A", "quote": "4 subsequent modifications (between 2007 and 2013)", "quotes": [ { "text": "had the effect of rendering capsules produced by competing manufacturers incompatible with the new models", "for": "What the investigation services found" }, { "text": "The Autorité accepts these commitments, makes them obligatory and decides to close the proceedings brought before it.", "for": "Commitments made binding" }, { "text": "a minimum of 4 months (compared to 3 months in the initial version)", "for": "Notice period in the commitments" } ], "scope": { "claim": "finding", "context": "Press release of a national competition authority summarising its commitments decision of 4 Sep 2014; practices described as liable to constitute an abuse, no fine", "checked": "2026-10-27T00:00:00.000Z" }, "accessed": "2026-10-27T00:00:00.000Z" } ], "markdown": "## What a capsule system is\n\nA coffee capsule is a closed container that holds one dose of ground coffee.2,3 It fits only the machines of its own system. The machine pierces the capsule and passes hot water through the grounds.6 According to a coffee science textbook chapter, almost all brewing parameters are fixed by the system, so that even inexperienced users can obtain a very good cup.12\n\nMost capsules studied for this entry brew a small, strong cup in the manner of espresso. In a 2013 comparison of nine brewing methods, a capsule brew reached more than 4% total solids, a strength the authors call typical of espresso.8 Other single-dose formats exist. Permeable pads, sealed filter pouches and drip bags are covered in Single-serve beyond capsules. What capsules are made of, and how EU law tells capsules from pads, is covered in Coffee packaging.\n\n## How a capsule brews\n\nThe patents describe the steps in order.2,4 The figure shows them in one drawing.\n\n1. **The chamber closes.** The machine clamps the capsule in its brewing chamber.2,4\n2. **The inlet is pierced.** An injection needle pierces the closed top of the capsule.2,4\n3. **Pressure builds.** Water fills the capsule. The outlet membrane bulges and is pressed against the holder.2,4\n4. **The outlet opens.** In a patent first filed in 1991, the membrane tears where it meets raised pyramids on the holder plate.4\n5. **The coffee flows out.** The brew passes between the torn parts of the membrane and leaves through the outlet.4\n\n
\n
\n

A capsule in the brewing chamber

\n
    \n
  1. Capsule body. A closed truncated cone; aluminium in the 1976 design.2
    2. \n
  2. Injection needle. Pierces the closed top and brings in hot water.2,4
    3. \n
  3. Ground coffee. One dose, sealed in at the factory.2,3
    4. \n
  4. Outlet membrane. Torn by the water pressure, not by the user.3,4
    5. \n
  5. Pyramid plate. Raised elements on which the membrane tears.4,6
    6. \n
  6. Seal. Closes the chamber against the capsule rim; moved from machine to capsule in 2007.6
    7. \n
  7. Brewing chamber. Holds the capsule while the water is under pressure.4
    8. \n
  8. Outlet. The brew flows on into the cup.2,4
    9. \n
\n
A closed capsule just after opening, after the construction in three Nestlé patents and the French competition decision. Point at a number or a line of the legend to highlight the part. Schematic, not to scale.2,3,4,6
\n
\n\nThe user never opens the capsule. In a patent first filed in 1991, the outlet face is meant to be torn solely by the pressure of the brewing water.3 The earlier 1976 design opened along a groove pressed into the membrane.2 In the capsules of a 2023 imaging study, the water ran from the top inlet to the bottom outlet.10\n\n## Dose, cup and strength\n\nStudies have weighed what is inside capsules. In a 2020 study of 43 capsule coffees of one shape, each capsule held 4.97–6.17 g of ground coffee.7 Other studies give 5–7 g per capsule.8,9,10 The chart sets the values side by side.\n\n
\n
\n
Ground coffee in one capsule as weighed or stated in four studies: 43 capsule products (2020), one product (2013), two compatible types (2022) and the Iperespresso-system capsules of an imaging study (2023). Means ± standard deviation where the study gives one.7,8,9,10
\n
\n\nThe cup is small. In the 2013 comparison, a capsule gave about 30 mL in 24 ± 2 s.8 In the 2020 study, every brew was stopped at about 40 g.7 The 43 coffees then reached extraction yields of 15.7–26%.7 Extraction yield, the share of the coffee that dissolves into the cup, is explained in Extraction yield and TDS.\n\nCapsules from one system can still brew very differently. In the 2020 study, the brewing time ranged from 10 to 41 s on one machine.7 More coffee or a finer grind raised the strength most efficiently.7 The quality scores of three certified Q graders were not correlated with the technical measures of the grounds.7\n\n## Formats and compatibility\n\nCapsules of different systems differ in how they open. In the Nestlé patents, the capsule has no outlet until the water pressure tears the membrane.3,4 A 1992 Keurig patent describes a different cartridge. It holds a filter element inside, and the machine pushes one needle through the lid and a second through the bottom.5\n\nCapsules for one system are also made by other firms. A coffee history chapter reports that other roasters introduced their own systems or sold Nespresso-compatible capsules.13 In France, compatible capsules went on sale from April 2010, according to the French competition authority.6 The authority’s decision describes machine changes to the seal, the piercing system and the extraction unit that affected such capsules.6\n\n## Where the system came from\n\nPatent records place the start of the capsule system in Switzerland. The earliest Nestlé capsule patent consulted was filed there on 17 December 1976.1 It names Eric Favre as inventor.1 Its US version, granted in 1979, describes an aluminium capsule closed by a membrane that breaks under water pressure.2\n\nTwo European patents filed in May 1992 describe the tearing outlet and the pyramid plate.3,4 All three name a Nestlé company as owner.1,3,4 In its preliminary assessment, the French competition authority states that Nespresso created and developed the technology of home espresso made from portioned coffee. It also states that Nestlé Nespresso, Nestec and Nestlé are based in Switzerland.6\n\n\n\n## Opening under pressure\n\n**The 1976 capsule.** The US patent of 1979 describes a body of sheet aluminium 60–110 µm thick, preferably 80 µm, shaped as an acute truncated cone with a rim at its base.2 The membrane closing the base carries a stamped groove, preferably C-shaped, as a line of weakness.2 Water pressure first makes the membrane expand and then breaks it along this line; the drink flows directly into the cup.2 The patent describes a polypropylene sieve with openings of 40–60 µm inside, and says the pressure may reach about 16 bar.2\n\n**The 1991 design.** The first European patent claims a closed cartridge whose outlet face is torn solely by the pressure of the extraction fluid.3 Its prior-art section cites CH 605293 as a capsule with weakened zones that tear under pressure.3 The second describes the holder: a raised surface with pyramid-shaped elements on which the lower face of the cartridge presses and tears.4 Tearing starts at the edges of the pyramid tops, the internal pressure partly drops, and the extract passes between the torn parts.4 The patent gives brewing pressures of 1–20 bar.4 Patents describe how a device is built; they are not evidence of how it performs.\n\n**Why the opening matters.** A membrane that opens only under pressure lets pressure build in the bed before any brew flows. No study consulted for this entry measured the opening pressure of a capsule or the pressure inside it during brewing. The 2020 study measured the pressure of the gas sealed in each capsule before brewing, by raising the pressure around the capsule in a closed vessel until its lid changed shape; this pressure was not correlated with the extraction dynamics.7 How the residual gas is managed in production is covered in How capsules are made.\n\n**The bed after brewing.** In a 2023 imaging study by X-ray microtomography, the coffee beds of Iperespresso-system capsules were less porous after extraction.10 Porosity decreased from the bottom outlet to the top inlet in the capsules scanned after brewing.10 The authors suggest that erosion of the coffee powder depends to some extent on pressure.10\n\n## Pressure and temperature as reported\n\nThe studies consulted report machine pressures, not pressures measured in the capsule. A 2013 study gives 19 bar for its capsule machine as information from the manufacturer.8 A 2022 study gives 19 bar for a Nespresso-system machine and 15 bar for a Dolce Gusto-system machine.9 The 2023 imaging study states 13 ± 1 bar and water at 97 ± 3 °C.10 No other study consulted for this entry states the water temperature in a capsule machine. The pressure at the bed of a conventional espresso machine is discussed in How an espresso machine works.\n\nA pump rating is not the pressure across the coffee. According to a coffee science textbook chapter, a pump delivers its highest pressures at the lowest flow rates, and the permeability of the bed decides the actual operating pressure.12 The same chapter calls pressure and coffee-to-water ratio in capsule systems comparable to those of barista espresso.12\n\n## Extraction across 43 capsules\n\nThe 2020 study extracted 43 Nespresso and compatible capsules of the same geometry on one machine and stopped every brew at about 40 g (40.1 ± 0.3 g).7 Its Table 1 gives, per product, 4.97–6.17 g of coffee, 2.15–3.64% total dissolved solids (TDS) and 15.7–26% extraction yield.7 The brew time ran from 10 to 41 s, which corresponds to mean flow rates of 1–4 g/s.7\n\n- **Grind and fines.** The share of fines below 100 µm ranged from 6 to 16% by volume.7 A larger share of fines went with longer brewing times; the median particle size alone was not correlated with brewing time.7 The general effects of grind are covered in Extraction variables.\n- **Dose and grind for strength.** More coffee in the capsule or a finer grind raised the TDS most efficiently.7\n- **Sensory quality.** Quality in the cup, scored by three certified Q graders, was not correlated with the technical variables of the grounds.7\n\nOur calculation from these values: dividing each product’s mean brew mass (39.6–40.7 g) by its mean coffee per capsule (4.97–6.17 g) gives 6.5–8.2 g of beverage per gram of coffee; the brew mass, not water used, is the basis. In the 2013 study, about 30 mL came from 5.5 ± 1.1 g, about 5.5 mL per gram (our calculation from the mean dose and nominal cup; volume, not mass).8 The same study traced the larger spread of the capsule’s extraction efficiency to variation in the coffee per capsule.8\n\n## Capsule and bar espresso compared\n\nTwo studies compared capsules with other methods. In a 2014 study, two capsule systems and a bar machine brewed the same roasted coffee with the same water.11 A principal component analysis separated the three techniques, and the two capsule systems gave the most reproducible results.11 In the 2013 comparison, the capsule brew had the most and darkest crema of the nine methods, but it used a different coffee from the others.8\n\nIn a 2022 study, crema from a 19 bar capsule system was more stable than crema from a 15 bar system.9 The two systems also differed in dose (5 and 7 g) and capsule, so pressure is not the only difference.9 How crema is measured is explained in Reading a shot.\n\n## Compatible capsules in France\n\nThe 2014 decision of the French competition authority describes changes to Nespresso machines between 2007 and 2013 and the arrival of compatible capsules.6 Compatible capsules were sold in France from 7 April 2010.6 Its investigation services found that four modifications to the machines between 2007 and 2013 had made capsules of competing makers incompatible with the new models.14 The authority considered such practices liable to constitute an abuse of a dominant position; it accepted commitments and closed the case without a fine or a finding of infringement.14\n\n| Change | Year | What changed |\n|---|---|---|\n| Seal | 2007 | Seal moved from the machine’s extraction cage to the capsule6 |\n| Flowmeter | From 2009 | A flowmeter developed by the company itself6 |\n| Ribs, hooks and grooves | July 2010 (one model) or 2011 (the decision gives both) | Added to the machines6 |\n| Piercing system | 2013 | A new perforation system6 |\n\nNespresso committed to notify makers of compatible capsules of technical changes at least 4 months before new machines reach the market, against 3 months in its first offer.14 The authority made the commitments binding on 4 September 2014.14\n\n**Patent expiry.** A European patent runs for at most 20 years from filing, so the two patents filed in May 1992 could not run beyond May 2012 (our reading of the dates). The patent register lists both as expired, with an estimated expiry in May 2012.3,4 A coffee history chapter dates the expiry of many patents on the system to 2012.13 Which patents protected which capsule features in which country was not checked for this entry.\n\n## Reference values\n\n| Parameter | Value reported | Context | Source |\n|---|---|---|---|\n| Coffee per capsule | 4.97–6.17 g | 43 Nespresso-system products, Table 1, n = 3 each | Eiermann et al.7 |\n| Coffee per capsule | 5.5 ± 1.1 g | One Nespresso product, 10 capsules | Gloess et al.8 |\n| Coffee per capsule | 5 g; 7 g | Nespresso-compatible; Dolce Gusto-compatible | Lomolino et al.9 |\n| Coffee per capsule | 6.7 ± 0.1 g | Iperespresso-system capsules, imaging study | Mo et al.10 |\n| Beverage | ≈30 mL | One product | Gloess et al.8 |\n| Beverage | 40.1 ± 0.3 g (39.6–40.7 g) | Brews stopped by weight | Eiermann et al.7 |\n| Brew time | 24 ± 2 s | One product | Gloess et al.8 |\n| Brew time | 10–41 s | 43 products, one machine | Eiermann et al.7 |\n| Total dissolved solids | 2.15–3.64% | 43 products, ≈40 g brews | Eiermann et al.7 |\n| Total solids | Above 4% | One product, ≈30 mL | Gloess et al.8 |\n| Extraction yield | 15.7–26% | 43 products, ≈40 g brews | Eiermann et al.7 |\n| Fines below 100 µm | 6–16% by volume | 43 products | Eiermann et al.7 |\n| Machine pressure (stated) | 19 bar; 15 bar; 13 ± 1 bar | Manufacturer or study data, not measured in the capsule | Gloess et al.8; Lomolino et al.9; Mo et al.10 |\n| Water temperature (stated) | 97 ± 3 °C | One imaging study | Mo et al.10 |\n| Pressure in the patents | Up to about 16 bar (1976 design); 1–20 bar (1991 design) | Patent descriptions, not measurements | Favre2; Fond et al.4 |\n| Body sheet (1976 design) | Aluminium 60–110 µm, preferably 80 µm | Patent | Favre2 |\n\n## Open questions\n\n- **Pressure in the capsule.** No study consulted for this entry measured the pressure at which the membrane opens or the pressure across the bed during brewing.\n- **Temperature in the cup.** Only one study consulted states a water temperature, and none measured the brew temperature at the coffee.\n- **Compatible capsules.** No peer-reviewed study consulted compared original and compatible capsules on the same machine for opening, flow and extraction; the 2020 study mixed both without reporting them separately.7\n- **Other systems.** The studies consulted cover Nespresso-type capsules, one Dolce Gusto-type system and Iperespresso-system capsules in one imaging study. No study consulted measured dose or extraction for filter-type cartridges such as those in the Keurig patent.5\n\n## Key studies\n\n
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Eiermann et al., 2020 – What governs capsule extraction. Extracts 43 capsule coffees of one geometry on one machine to 40 g and relates the grounds to the brew. Coffee per capsule, TDS and yield varied widely; the share of fines governed brewing time, and more coffee or a finer grind raised strength most efficiently.

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Scientific Reports 10, 17079 · doi:10.1038/s41598-020-74138-1

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Parenti et al., 2014 – Capsule and bar espresso. Brews the same coffee with two capsule systems and a traditional bar machine; nine espressos were analysed. Physico-chemical and aroma data separate the three techniques, and the capsule systems were the most reproducible.

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Journal of Food Engineering 121, 112–117 · doi:10.1016/j.jfoodeng.2013.08.031

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Gloess et al., 2013 – Nine methods side by side. Records dose, cup, time and pressure for nine methods, among them one capsule product. The capsule brew was espresso-strength, with the most and darkest crema; its efficiency varied with the coffee per capsule.

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European Food Research and Technology 236, 607–627 · doi:10.1007/s00217-013-1917-x

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Mo et al., 2023 – Inside a spent capsule bed. Images the beds of Iperespresso-system capsules by X-ray microtomography before and after brewing and simulates flow through them. The beds lost porosity during extraction, with porosity falling from outlet to inlet.

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Scientific Reports 13, 16374 · doi:10.1038/s41598-023-42380-y

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