It is characterized by its small serving size, typically 25–30 ml, and its distinctive layers: a dark body topped with a lighter-colored foam called "crema".

Espresso machines use pressure to extract a highly concentrated coffee with a complex flavor profile in a short time, usually 25–30 seconds.

The result is a beverage with a higher concentration of suspended and dissolved solids than regular drip coffee, giving espresso its characteristic body and intensity.

[3][4] Despite the stronger taste profile, espresso typically contains fewer milligrams of caffeine than a standard serving of drip-brewed coffee.

It can be made with various types of coffee beans and roast levels, allowing for a wide range of flavors and strengths.

The quality of an espresso is influenced by factors such as the grind size, water temperature, pressure, and the barista's skill in tamping the coffee grounds.

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.

[7] Modern espresso, using hot water under pressure, as pioneered by Gaggia in the 1940s, was originally called crema caffè (lit.

Italy uses the term espresso, substituting s for most x letters in Latin-root words, with the term deriving from the past participle of the Italian verb esprimere, itself derived from the Latin exprimere, which means 'to express', and refers to the process by which hot water is forced under pressure through ground coffee;[10][11] x is not considered part of the standard Italian alphabet.

[12] While the 'expresso' spelling is recognized as mainstream usage in some American dictionaries,[13][14] some cooking websites call the 'x' variant illegitimate.

[15][16][17] Oxford Dictionaries online states: "The spelling expresso is not used in the original Italian and is strictly incorrect, although it is common.

[19] The Oxford Dictionary of American Usage and Style (2000) describes the spelling expresso as "wrong", and specifies espresso as the only correct form.

[20] The third edition of Fowler's Modern English Usage, published by the Oxford University Press in 1996, noted that the form espresso "has entirely driven out the variant expresso (which was presumably invented under the impression that it meant 'fast, express')".

33/256 dated 16 May 1884 (according to the "Bollettino delle privative industriali del Regno d'Italia", 2nd Series, Volume 15, Year 1884, pp.

Seventeen years later, in 1901, Luigi Bezzera, from Milan, devised and patented several improvements to the espresso machine, the first of which was applied for on 19 December 1901.

This is due to the higher concentration of suspended and dissolved solids and the crema on top (a foam with a creamy consistency).

These oil droplets preserve some of the aromatic compounds that are lost to the air in other coffee forms, enhancing the strong flavor of espresso.

Espresso is made by forcing very hot water under high pressure through finely ground compacted coffee.

Farther north, the trend moves toward slightly lighter roasts, while outside Italy a wide range is popular.

[citation needed] The length of the shot can be ristretto (or stretto) (reduced), normale or standard (normal), or lungo (long):[45] 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 makes volume-based comparisons difficult (precise measurement uses the mass of the drink).