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    The capsule

    The capsule encloses a dose of ground coffee in a sealed container that the machine passes hot water through under pressure, then ejects after use. It removes the grinder, the weighing and the tamping, and has brought espresso into homes and offices.

    THE PROCESS IN MOTION

    What happens inside a capsule?

    Start the scene or choose a stage. The animation simplifies the mechanism; what follows gives the details and the available references.

    A sealed dose

    The ground coffee, dosed and tamped at the factory, waits in a container closed by a membrane: no more grinder or weighing, everything is decided in advance. Gloess measured 5.5 g of coffee per capsule, to within 1.1 g; the fineness of the grind is not disclosed by the manufacturer.

    Read the stages without animation
    1. A sealed doseThe ground coffee, dosed and tamped at the factory, waits in a container closed by a membrane: no more grinder or weighing, everything is decided in advance. Gloess measured 5.5 g of coffee per capsule, to within 1.1 g; the fineness of the grind is not disclosed by the manufacturer.
    2. The water entersCapsule slid in, machine closed: the machine injects hot water under pressure into the container. Pressure rises against the membrane, 19 bars claimed by the manufacturer of the machine used in the test.
    3. The membrane gives wayThe membrane opens along its line of weakness, the one described in Éric Favre's patent, and the coffee escapes through the opening it delimits. In Gloess's test, 30 mL flow in 24 seconds, give or take 2 seconds.
    4. The cremaThe passage under pressure makes the oils and gases foam. Lomolino and his colleagues find at 19 bars a very stable crema with very fine bubbles, at 15 bars more unstable foams with irregular bubbles; Gloess finds that the capsule has the most abundant and darkest crema of his test.
    5. The used capsuleThe empty container, with its grounds, is discarded: one cup, one package to collect. The inventor of the American filter cartridge said in 2015 that he sometimes regrets an invention made of a four-layer plastic that he judged impossible to recycle.

    To remember: The capsule does at the factory everything that comes before the water: the machine only has to push water at high pressure until the membrane opens.

    In history: Éric Favre files with Nestlé, on December 17, 1976, the Swiss patent for a capsule sealed by a membrane; the system is launched in 1986.

    Read the full article and its sources ↓
    FamilyPressure
    Also calledpod, Nespresso, K-Cup
    Landmark1976, Éric Favre, Nestlé, Switzerland; 1992, John Sylvan and Peter Dragone, Keurig, United States

    History

    The engineer Éric Favre, son of an agricultural inventor, joined the packaging department of Nestlé's Swiss headquarters in 1975 (source 3). His wife, who was Italian, mocked a Switzerland that did not know how to make coffee; Favre says he wanted to prove to her that he could make the best espresso, and the couple searched for the ideal cup as far as the Caffè Sant'Eustachio, in Rome (sources 3 and 4). Swiss patent 605,293, filed on December 17, 1976 in the name of Favre and Nestlé, is the first piece of the system (source 1); its American equivalent, granted on January 23, 1979, describes a sealed capsule in the shape of a truncated cone with a rim, closed by a membrane whose line of weakness delimits the opening (source 2).

    Internal resistance was strong: in a company whose instant coffee sold very well, the home espresso machine seemed superfluous. Nespresso was launched in 1986 with Favre at its head, had a difficult start, and Favre left Nestlé in 1991 (source 4) to found Monodor, which makes competing capsules (source 3). Success is also measured by Italian irritation: the historian Jonathan Morris reports that Lavazza took Nespresso to court in 2010 over its advertising, and that the Italian coffee world saw in the capsule a counterfeit of espresso (source 5).

    In the United States, the path is parallel. John Sylvan and Peter Dragone file for Keurig, on September 16, 1992, the patent for a filter cartridge: a waterproof, pierceable cup, divided by a filter element into two chambers, one that contains the coffee, the other, empty, from which the drink comes out (source 8). Sylvan had conceived it for offices (source 10). It relies on a filter, as its name indicates (source 8), but shares with the capsule the dose enclosed at the factory.

    The system lived off its patents and opened up when they expired. European protection of the Nespresso capsules expired in May 2011; Nestlé then tried to assert a more recent patent, which the High Court of London judged not infringed by Dualit's compatible capsules, and invalid for lack of novelty, on April 22, 2013 (source 9). Several key patents had lapsed in 2011, which opened the market to competitors (source 4). The 1992 Keurig patent reached expiration on September 16, 2012 according to Google Patents (source 8).

    The motion

    The motion boils down to three movements: slide the capsule in, close, press. Hot water enters under pressure and the membrane opens along its line of weakness to let the coffee out, according to the principle described by Favre (source 2). In Gloess's test, one capsule contained 5.5 g of coffee on average, to within 1.1 g, for about 30 mL of drink in 24 seconds, under 19 bars claimed by the machine's manufacturer (source 6).

    Everything else, grind, dose and tamping, is decided at the factory; Gloess could not learn the fineness of the grind, which the manufacturer does not disclose (source 6). Morris notes that a Nespresso capsule contained 5 g of coffee for a 40 mL cup, whereas the Italian espresso institute requires 7 g for 25 mL (source 5).

    The settings

    • GrindSet by the manufacturer and not disclosed (source 6).
    • Dose5.5 g to within 1.1 g, measured by Gloess (source 6); 5 g according to Morris (source 5).
    • Brew ratioAbout 1:5.5 in Gloess's test (5.5 g for 30 mL, calculated) (source 6).
    • TemperatureNot disclosed by the manufacturer (source 6).
    • Time24 seconds, give or take 2 seconds, in Gloess's test (source 6).
    • Pressure19 bars claimed by the machine's manufacturer (source 6); compatible capsules tested at 15 and 19 bars by Lomolino (source 7).

    What it has going for it

    • You get an espresso without a grinder or adjustment: grind, dose and tamping are done in advance (source 5).
    • The crema is abundant: in Gloess's test, the capsule gave the most abundant and darkest crema of the five crema-producing drinks (source 6).
    • Gloess's panel finds it has the highest body, more than its dry matter would predict, probably because of this crema (source 6).
    • The ground coffee stays enclosed in a sealed capsule until use (source 2).

    What is held against it

    • The coffee is not ground at the last minute and the dose is lower than that of Italian espresso, hence a cup that Morris calls more watery (source 5).
    • The dose varies more than one might think: Gloess attributes the greater spread of his extraction measurements to the variability of the coffee per capsule (source 6).
    • Every cup leaves a package: the inventor of the K-Cup said in 2015 that he sometimes regrets his invention, made of a four-layer plastic that he judged impossible to recycle (source 10). Collection and recycling figures are dealt with in plate XIII (source 11).
    • The system ties the cup to a machine and its patents: it took a lawsuit, lost by Nestlé in London in 2013, for compatible capsules to be admitted (source 9).

    What it gives in the cup

    Gloess's test tasted a Nespresso capsule alongside espressos from professional machines. He finds it has the most abundant and darkest crema, a strong roasted note, the highest body, the most acidic pH of the nine methods (5.51) and a negligible fatty acid content, warning that the coffee was not the same as for the other preparations (source 6). Like the other espressos in the test, it exceeded 4% dry matter (source 6).

    Pressure matters for crema. Lomolino and his colleagues, with compatible capsules and machines, find at 19 bars a very stable crema with very fine bubbles, at 15 bars more unstable foams with irregular bubbles, and sensory profiles that follow the pressure (source 7). On the drinker's side, Ferini and her colleagues showed that consumers instinctively sort espresso and capsule together, but that on tasting they perceive them as different drinks (source 12).

    Anecdotes

    • At the Caffè Sant'Eustachio, Favre observes that the barista, Mr. Eugenio, who still worked on an old four-piston machine, works the piston three or four times instead of one; Favre concludes that the barista aerates the coffee, the air oxidizing aromas and oils so that they extract faster (source 3).

    The sources for this sheet

    1. Éric Favre and Nestlé SA, Swiss patent CH 605,293 A5, filed December 17, 1976, published September 29, 1978 (Google Patents record) · online · primary · reading: yes (bibliographic record; text not available on the record)
    2. Éric Favre, Société d'assistance technique pour produits Nestlé, US patent 4,136,202, “Capsule for beverage preparation,” filed December 7, 1977 (priority of December 17, 1976), granted January 23, 1979 · online · primary · reading: yes (abstract and bibliographic data)
    3. WIPO, WIPO Magazine, “Anyone for coffee? The story behind the coffee capsule,” September 1, 2010 · online · institutional
    4. AFP, “Nespresso inventor says wife and Rome cafe inspired the pod,” The Local (Switzerland), August 21, 2016 · online · press
    5. Jonathan Morris, “Making Italian Espresso, Making Espresso Italian,” Food and History, vol. 8, no. 2, 2010, p. 155-183, DOI 10.1484/J.FOOD.1.102222 (author's preprint, University of Hertfordshire) · online · academic
    6. Alexia N. Gloess et al., “Comparison of nine common coffee extraction methods: instrumental and sensory analysis,” European Food Research and Technology, vol. 236, 2013, p. 607-627, DOI 10.1007/s00217-013-1917-x · online · academic
    7. Giovanna Lomolino et al., “Foam Characteristics and Sensory Analysis of Arabica Coffee, Extracted by Espresso Capsule and Moka Methods,” Beverages, vol. 8, no. 2, 2022, article 28, DOI 10.3390/beverages8020028 (abstract read) · online · academic · reading: abstract only
    8. John E. Sylvan and Peter B. Dragone (Keurig Inc.), US patent 5,325,765, “Beverage filter cartridge,” filed September 16, 1992, granted July 5, 1994; expiration according to Google Patents · online · primary
    9. Brian Cordery (Bristows), “Green light for UK Nespresso capsule market,” Kluwer Patent Blog, May 1, 2013 · online · secondary
    10. HuffPost Canada, “K-Cup inventor John Sylvan regrets...,” March 6, 2015, which reprises the interviews of The Atlantic and CBC (As It Happens) · online · press · reading: yes (relay; The Atlantic article could not be opened)
    11. PXL Roasters, plate XIII “What we throw away,” section 12, Capsules (dechets-12.html) · internal
    12. Juliana L. Ferini et al., “Consumers' perception of different brewed coffee extractions using the sorting technique,” Journal of Sensory Studies, vol. 36, no. 2, online in 2020, DOI 10.1111/joss.12633 (abstract) · online · academic · reading: abstract only
    Elsewhere on the sitePreparationsEspresso today: machines, motion, profilingThe section of the plate that deals with it.PreparationsTodayThe section of the plate that deals with it.What we throw awayCapsulesAnother page of the site that deals with it.
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