Editing Espresso (section)

==Characteristics==
Espresso is generally thicker than coffee brewed by other methods, with a viscosity similar to that of warm honey. This is due to the higher concentration of [[Suspended solids|suspended]] and [[dissolved solids]] and the crema on top (a foam with a creamy consistency).<ref>Illy, "Il caffè e i cinque sensi" [http://www.illy.com/wps/wcm/connect/it/caffe/degustazione-caffe]: "La tazzina di porcellana bianca incornicia la crema: una trama sottile nei toni del nocciola, percorsa da leggere striature rossastre"</ref> As a result of the pressurized brewing process, the flavors and chemicals in a typical cup of espresso are very concentrated.

Espresso contains more [[caffeine]] per unit volume than most coffee beverages, but as its usual serving size of 25–30 ml (1 US oz) is much smaller than other coffee drinks, the overall caffeine content of a single "serving" of espresso is generally lower than that of other coffees.<ref name="Mr. Coffee blog post">{{cite web|title=The Great Debate: Does Espresso or Drip Coffee Have More Caffeine?|url=http://www.mrcoffee.com/blog/archive/2014/october/the-great-debate%3A-does-espresso-or-drip-coffee-have-more-caffeine%3F.html|publisher=[[Mr. Coffee]]|date=24 October 2014|access-date=21 June 2015|archive-date=22 May 2019|archive-url=https://web.archive.org/web/20190522222417/https://www.mrcoffee.com/blog/archive/2014/october/the-great-debate:-does-espresso-or-drip-coffee-have-more-caffeine?.html|url-status=dead}}</ref> While the exact caffeine content of any coffee drink will vary, a typical {{convert|30|ml|USoz|0|abbr=off}} serving of espresso contains approximately 65 milligrams of caffeine, but a typical {{convert|240|ml|USoz|0|abbr=off}} serving of drip coffee contains 150–200&nbsp;mg of caffeine.<ref>{{cite web|url=http://ndb.nal.usda.gov/ndb/foods/show/4291|archive-url=https://web.archive.org/web/20131124143904/http://ndb.nal.usda.gov/ndb/foods/show/4291 |title=Show Foods|archive-date=24 November 2013}}</ref><ref>[http://www.mayoclinic.com/health/caffeine/AN01211 How much caffeine is in your daily habit?]</ref><ref>{{cite web|url=http://ndb.nal.usda.gov/ndb/foods/show/4290|archive-url=https://web.archive.org/web/20131122090248/http://ndb.nal.usda.gov/ndb/foods/show/4290 |title=Show Foods|archive-date=22 November 2013}}</ref>

The three dispersed phases in espresso are what make the beverage unique. The first dispersed phase is an emulsion of oil droplets. The second phase is suspended solids, while the third is the layer of gas bubbles or foam. The dispersion of very small oil droplets is perceived in the mouth as creamy. This characteristic of espresso contributes to what is known as the body of the beverage. 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.{{sfn|Illy|Viani|2005}}

The crema is a layer of dense foam that forms on top of the drink.<ref>{{cite web |title=What is Crema? |url=http://www.seattlecoffeegear.com/learn/coffee-101/articles/what-is-crema |url-status=dead |archive-url=https://web.archive.org/web/20130512211256/http://www.seattlecoffeegear.com/learn/coffee-101/articles/what-is-crema |archive-date=12 May 2013 |access-date=8 June 2013 |publisher=seattlecoffeegear}}</ref><ref>{{cite web |title=Espresso Crema |date=7 October 2014 |url=http://www.chemistryviews.org/details/ezine/6372721/Espresso_Crema.html |access-date=8 October 2014 |publisher=ChemistryViews.org}}</ref> It consists of [[Emulsion|emulsified]] oils in the ground coffee turned into a [[colloid]], which does not occur in other brewing methods. Crema is produced when water placed under very high pressure dissolves more carbon dioxide, a gas present inside the coffee that is produced during the roasting process.<ref name="The World Atlas Of Coffee">{{Cite book|last=Hoffmann|first=James|author-link=James Hoffmann|title=The World Atlas of Coffee 2nd Edition|publisher=Mitchell Beazley|year=2018|isbn=978-1-78472-429-0|location=Great Britain|language=English}}</ref>{{rp|96}}

Espresso is served on its own, and is also used as the base for various other coffee drinks, including [[caffè latte]], [[cappuccino]], ''[[caffè macchiato]]'', ''[[caffè mocha]]'', [[flat white]], and [[Caffè americano|americano]].