Espresso (/ɛˈspɹɛsəʊ/ italian: /eˈsprɛsso/) is coffee brewed by forcing a small amount of nearly boiling water under pressure through finely ground coffee beans. Espresso is generally thicker than coffee brewed by other methods, has a higher concentration of suspended and dissolved solids, and has crema on top (a foam with a creamy consistency). As a result of the pressurized brewing process, the flavors and chemicals in a typical cup of espresso are very concentrated. Espresso is the base for other drinks, such as a caffè latte, cappuccino, caffè macchiato, cafe mocha, or caffè Americano. Espresso has more caffeine per unit volume than most beverages, but the usual serving size is smaller—a typical 60 mL (2 US fluid ounces) of espresso has 80 to 150 mg of caffeine, a little less than the 95 to 200 mg of a standard 240 mL (8 US fluid ounces) cup of drip-brewed coffee.
Espresso is made by forcing very hot (about 95° C) water under high pressure through finely ground, compacted coffee. Tamping down the coffee promotes the water's even penetration of the grounds. This process produces an almost syrupy beverage by extracting both solid and dissolved components. The "crema"  is produced by emulsifying the oils in the ground coffee into a colloid, which does not occur in other brewing methods. There is no universal standard defining the process of extracting espresso, but there are several published definitions which attempt to place constraints on the amount and type of ground coffee used, the temperature and pressure of the water, and the rate of extraction. Generally, one uses an espresso machine to make espresso. The act of producing a shot of espresso is often termed "pulling" a shot, originating from lever espresso machines, which require pulling down a handle attached to a spring-loaded piston, forcing hot water through the coffee at high pressure. Today, however, it is more common for the pressure to be generated by an electric pump.
The technical parameters outlined by the Italian Espresso National Institute for making a Certified Italian Espresso, are as follows: 
|Portion of ground coffee||7 g ± 0.5|
|Exit temperature of water||88°C ± 2°C|
|Temperature in cup||67°C ± 3°C|
|Entry water pressure||9 bar ± 1|
|Percolation time||25 seconds ± 5|
|Volume in cup (including froth)||25 ml ± 2.5|
Espresso is both a coffee beverage and a brewing method. It is not a specific bean, bean blend, or roast level. Any bean or roasting level can be used to produce authentic espresso. For example, in southern Italy, a darker roast is generally preferred. Farther north, the trend moves toward slightly lighter roasts, while outside Italy, a wide range is popular.
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Espresso has risen in popularity worldwide since the 1980s. In the United States, cafés serve many variations by adding syrup, whipped cream, flavour extracts, soy milk, and spices to their drinks. The American Pacific Northwest has been viewed as the driver behind this trend. The popularity later spread to shops in other regions and into homes as kitchen-friendly machines became available at moderate cost. In other parts of the world, espresso has long been the customary method of coffee preparation in restaurants, bars and coffee shops.
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Angelo Moriondo’s Italian patent for a steam-driven "instantaneous" coffee beverage making device, which was registered in Turin in 1884 (No. 33/256), is notable. Author Ian Bersten, whose history of coffee brewers is cited below, claims to have been the first to discover Moriondo’s patent. Bersten describes the device as “… almost certainly the first Italian bar machine that controlled the supply of steam and water separately through the coffee” and Moriondo as “... certainly one of the earliest discoverers of the expresso [sic] machine, if not the earliest.” Unlike true espresso machines, it was a bulk brewer, and did not brew coffee “expressly” for the individual customer.
Seventeen years later, in 1901, Milanese Luigi Bezzera came up with a number of improvements to the espresso machine. He patented a number of these, the first of which was applied for on the 19th of December 1901. It was titled “Innovations in the machinery to prepare and immediately serve coffee beverage” (Patent No. 153/94, 61707, granted on the 5th of June 1902).
In 1905, the patent was bought by Desiderio Pavoni, who founded the “La Pavoni” company and began to produce the machine industrially (one a day) in a small workshop in Via Parini in Milan.
The popularity of espresso developed in various ways; a detailed discussion of the spread of espresso is given in (Morris 2007), which is a source of various statements below.
In Italy, the rise of espresso consumption was associated with urbanization, espresso bars providing a place for socialization. Further, coffee prices were controlled by local authorities, provided the coffee was consumed standing up, encouraging the "stand at a bar" culture.
In the English-speaking world, espresso became popular, particularly in the form of cappuccino, due to the tradition of drinking coffee with milk and the exotic appeal of the foam; in the United States, this was more often in the form of lattes, with or without flavored syrups added. The latte is claimed to have been invented in the 1950s by Italian American Lino Meiorin of Caffe Mediterraneum in Berkeley, California, as a long cappuccino, and was then popularized in Seattle, and then nationally and internationally by Seattle-based Starbucks in the late 1980s and 1990s.
In the United Kingdom, espresso grew in popularity among youth in the 1950s, who felt more welcome in the coffee shops than in public houses (pubs).
Espresso was initially popular, particularly within the Italian diaspora, growing in popularity with tourism to Italy exposing others to espresso, as developed by Eiscafès established by Italians in Germany.
Initially, expatriate Italian espresso bars were downmarket venues, serving the working class Italian diaspora – and thus providing appeal to the alternative subculture / counterculture; this can still be seen in the United States in Italian American neighborhoods, such as Boston's North End, New York's Little Italy, and San Francisco's North Beach. As specialty coffee developed in the 1980s (following earlier developments in the 1970s and even 1960s), an indigenous artisanal coffee culture developed, with espresso instead positioned as an upmarket drink.
Today, coffee culture commentators distinguish large chain, midmarket coffee as "Second Wave Coffee", and upmarket, artisanal coffee as Third Wave Coffee.
In the Middle East, espresso is growing in popularity, with the opening of Western coffee shop chains.
Café vs. home preparation
A distinctive feature of espresso, as opposed to brewed coffee, is espresso's association with cafés, due both to the specialized equipment and skill required, thus making the enjoyment of espresso a social experience.
Home espresso machines have increased in popularity with the general rise of interest in espresso. Today, a wide range of home espresso equipment can be found in kitchen and appliance stores, online vendors, and department stores. The first espresso machine for home use was the Gaggia Gilda. Soon afterwards, similar machines such as the Faema Faemina, FE-AR La Peppina and VAM Caravel followed suit in similar form factor and operational principles. These machines still have a small but dedicated share of fans. Until the advent of the first small electrical pump-based espresso machines such as the Gaggia Baby and Quickmill 810, home espresso machines would not find widespread adoption. In recent years, the increased availability of convenient counter-top fully automatic home espresso makers and pod-based espresso serving systems has increased the quantity of espresso consumed at home.
Etymology and usage of the term
The origin of the term "espresso" is the subject of considerable debate. Although some Anglo-American dictionaries simply refer to "pressed-out", "espresso," much like the English word "express", conveys the senses of "just for you" and "quickly," which can be related to the method of espresso preparation.
The words express, expres and espresso each have several meanings in English, French and Italian. The first meaning is to do with the idea of "expressing" or squeezing the flavour from the coffee using the pressure of the steam. The second meaning is to do with speed, as in a train. Finally there is the notion of doing something "expressly" for a person ... The first Bezzera and Pavoni espresso machines in 1906 took 45 seconds to make a cup of coffee, one at a time, expressly for you.
The spelling espresso is widely considered correct while expresso appears as a less common variant. Italy uses the term espresso, substituting most x letters in Latin root words with s; x is not considered part of the standard Italian alphabet. Italian people commonly refer to it simply as caffè (coffee), espresso being the ordinary coffee to order; in Spain, while café expreso is seen as the more "formal" denomination, café solo (alone, without milk) is the usual way to ask for it when at an espresso bar.
Modern espresso, using hot water under pressure, as pioneered by Gaggia in the 1940s, was originally called crema caffè, in English "cream coffee", as can be seen on old Gaggia machines, due to the crema. This term is no longer used, though crema caffè and variants (caffè crema, café crema) find occasional use in branding.
While the 'expresso' spelling is recognized as mainstream usage in some American dictionaries, its inclusion is controversial, with many outright calling the 'x' variant illegitimate. Oxford Dictionaries online states "The spelling expresso is not used in the original Italian and is strictly incorrect, although it is common."
Cafés may have a standardized shot (size and length), such as "triple ristretto", only varying the number of shots in espresso-based drinks such as lattes, but not changing the extraction – changing between a double and a triple requires changing the filter basket size, while changing between ristretto, normale, and lungo may require changing the grind, which is less easily accommodated in a busy café, as fine tweaking of the grind is a central aspect to consistent quality espresso-making.
The size can be a single, double, or triple, which corresponds roughly to a 1, 2, and 3 US fluid ounce (approximately 30, 60 or 90ml) standard (normale) shot, and use a proportional amount of ground coffee, roughly 7–8, 14–16, and 21–24 grams; correspondingly sized filter baskets are used. The Italian term doppio is often used for a double, with solo and triplo being more rarely used for singles and triples. The single shot is the traditional shot size, being the maximum that could easily be pulled on a lever machine, while the double is the standard shot today.
Single baskets are sharply tapered or stepped down in diameter to provide comparable depth to the double baskets and, therefore, comparable resistance to water pressure. Most double baskets are gently tapered (the "Faema model"), while others, such as the La Marzocco, have straight sides. Triple baskets are normally straight-sided.
Portafilters will often come with two spouts, usually closely spaced, and a double-size basket – each spout can optionally dispense into a separate cup, yielding two solo-size (but doppio-brewed) shots, or into a single cup (hence the close spacing). True solo shots are rare, with a single shot in a café generally being half of a doppio shot.
In espresso-based drinks, particularly larger milk-based drinks, a drink with three or four shots of espresso will be called a "triple" or "quad", respectively, but this does not mean the shots themselves are triple or quadruple shots. Rather, generally double shots will be used, with one and a half shots used in a triple (split via the two spouts), and two shots used in a quad.
The length of the shot can be ristretto (reduced), normale/standard (normal), or lungo (long): these may correspond to a smaller or larger drink with the same amount of ground coffee and same level of extraction, or to different length of extraction. Proportions vary, and the volume (and low density) of crema make volume-based comparisons difficult (precise measurement uses the mass of the drink), but proportions of 1:1, 1:2, and 1:3–4 are common for ristretto, normale, and lungo, corresponding to 1, 2, and 3–4 US fl oz (30 ml, 60 ml, 90–120 ml) for a double shot. Ristretto is the most commonly used of these terms, and double or triple ristrettos are particularly associated with artisanal espresso.
Ristretto, normale, and lungo may not simply be the same shot, stopped at different times – which may result in an underextracted shot (if run too short a time) or an overextracted shot (if run too long a time). Rather, the grind is adjusted (finer for ristretto, coarser for lungo) so the target volume is achieved by the time extraction finishes.
A significantly longer shot is the caffè crema, which is longer than a lungo, ranging in size from 4–8 US fl oz (120–240 ml), and brewed in the same way, with a coarser grind.
The method of adding hot water produces a milder version of original flavor, while passing more water through the load of ground coffee will add other flavors to the espresso, which might be unpleasant for some people.
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In addition to being served alone, espresso is frequently blended, notably with milk (either steamed (without significant foam), wet foamed ("microfoam"), or dry foamed) and with hot water. Notable milk-based espresso drinks, in order of size, include: macchiato, cappuccino, flat white, and latte, while espresso and water drinks especially include the Americano and long black. Others include the red eye and latte macchiato. The cortado and galão are made primarily with steamed milk with little or no foam.
In order of size, these may be organized as follows:
- Traditional macchiato: 35–40 ml, one shot (30 ml) with a small amount of milk (mostly steamed, with slight foam so there is a visible mark)
- Modern macchiato: 60 ml or 120 ml, one or two shots (30 or 60 ml), with 1:1 milk
- Cortado: 60 ml, one shot with 1:1 milk, little foam
- Piccolo Latte: 90 ml, one shot with 1:2 milk, little foam
- Galão: 120 ml, one shot with 1:3 milk, little foam
- Flat white: 150 ml, one or two shots (30 or 60 ml), with 1:4 or 2:3 milk
- Cappuccino: 150–180 ml, one or two shots (30 or 60 ml), with wet foam.
- Latte: 240–600 ml, two or more shots (60 ml), with 1:3–1:9 milk
Some common combinations may be organized graphically as follows:
|frothed milk||hot water|
|espresso is on||top||latte macchiato||long black|
|bottom||caffè latte||caffè americano|
Methods of preparation differ between drinks and between baristas. For macchiatos, cappuccino, flat white, and smaller lattes and Americanos, the espresso is brewed into the cup, then the milk or water is poured in. For larger drinks, where a tall glass will not fit under the brew head, the espresso is brewed into a small cup, then poured into the larger cup; for this purpose a demitasse or specialized espresso brew pitcher may be used. This "pouring into an existing glass" is a defining characteristic of the latte macchiato and classic renditions of the red eye. Alternatively, a glass with "existing" water may have espresso brewed into it – to preserve the crema – in the long black. Brewing onto milk is not generally done.
- How much caffeine is in your daily habit? – MayoClinic.com
- Davids, Kenneth. Espresso: ultimate coffee. St. Martin's Press. p. 3. ISBN 0-312-24666-8.
- "Espresso Tamping". CoffeeResearch.org. Retrieved 2013-12-08.
- "What is Crema?". seattlecoffeegear. Retrieved 8 June 2013.
- "Today's Espresso Scene". Home Barista. Retrieved 29 April 2011.
- "Espresso Coffee". Coffee Research Institute. Retrieved 29 April 2011.
- "L'Espresso Italiano Certificato". Istituto Nazionale Espresso Italiano. Retrieved 29 April 2011.
- "Espresso Italiano Certificato". Istituto Nazionale Espresso Italiano. Retrieved 15 February 2013.
- The Book of Coffee, Francesco Illy, Ricardo Illy, 1992
- Bersten, p. 105
- "Caffe Mediterraneum – Invention of the Caffe Latte". Retrieved 2009-04-19.
- Bersten, p. 131
- Bersten, p. 132-133
- "espresso". Oxford English Dictionary. Oxford University press. 1989. Retrieved 2009-10-30.
- Bersten, p. 99
- Dictionary.com entry of expresso; Merriam Webster
- Morris, Jonathan (2007). "The Cappuccino Conquests. The Transnational History of Italian Coffee".
- Expresso – Definition and More from the Free Merriam-Webster Dictionary. Merriam-webster.com (2010-08-13). Retrieved on 2011-02-13.
- Expresso | Define Expresso at Dictionary.com. Dictionary.reference.com. Retrieved on 2011-02-13.
- What is espresso? Or is it expresso?. Homecooking.about.com (2010-06-14). Retrieved on 2011-02-13.
- What is espresso?, 1st in Coffee explains espresso coffee, Pressure brewed coffee from Italy. 1stincoffee.com. Retrieved on 2011-02-13.
- What is Espresso. Espresso People. Retrieved on 2011-02-13.
- Expresso or Espresso, English for students
- Definition of espresso from Oxford Dictionaries Online. Oxforddictionaries.com. Retrieved on 2011-02-13.
- Brewing ratios for espresso beverages
- Anatomy of a Triple Ristretto, by Jeremy Gauger, Gimme Coffee, Mar 17, 2009 – images and explanation
- "The Basics of Making Espresso - Tips and Techniques for Brewing". CupAndBrew.com. Retrieved 16 February 2014.
- Bersten, Ian (1993). Coffee Floats Tea Sinks: Through History and Technology to a Complete Understanding. Helian Books. ISBN 0-646-09180-8.
- Morris, Jonathan (2007), The Cappuccino Conquests. The Transnational History of Italian Coffee, website, 
- Dean, Adam. "The Founding Fathers of Espresso".
- Fumagalli, Ambrogio (1995). Coffee Makers. Chronicle Books. ISBN 0-8118-1082-8.
- Illy, Andrea; Viani, Rinantonio. Espresso: The Science of Quality. Academic Press. ISBN 0-12-370371-9.
- Illy, Francesco; Illy, Riccardo (1989/1992). The Book of Coffee. Milano: Abbeville Press. ISBN 1-55859-321-7.