Espresso coffee is a concentrated coffee beverage brewed by forcing very hot, but not boiling, water under high pressure through coffee that has been ground to a consistency that is between extremely fine and powder. Espresso coffee was invented by Edward Loysel de Santais in 1843. Santais's machine impressed visitors to the Paris Exposition of 1855 by producing 2000 cups of coffee in 1 hour.
Espresso coffee was developed in Milan, Italy in the early 20th century, but until the mid-1940s it was a beverage produced solely with steam pressure. The invention of the spring piston lever machine and its subsequent commercial success changed espresso into the beverage we know today. Espresso is now produced with between 9 and 10 atmospheric pressure.
The defining characteristics of espresso include a thicker consistency than drip coffee, a higher amount of dissolved solids than drip coffee per relative volume, and a serving size that is usually measured in shots, which is about 30ml (1-2 ounces) in size.
Espresso is chemically complex and volatile, with many of its chemical components degrading from oxidation or loss of temperature. Properly brewed espresso has three major parts: the heart, body and, the most distinguishing factor, the presence of crema, reddish-brown foam that floats on the surface of the espresso.
Preparation of espresso requires an espresso coffee machine, as it is the process that makes espresso the beverage that it is. Freshly brewed espresso must be served or mixed into other coffee beverages immediately, or it will begin to degrade due to cooling and oxidation.
Temperature and time of consumption are important variables that must be observed to enjoy an ideal espresso; it should be consumed within 2 minutes from when it is served.
A professional operator of an espresso coffee machine is called a barista or a bartender. In Italy and other parts of Europe, the barista is considered a career position, often with skills and training passed down from generation to generation. In other parts of the world, the job of the barista has been frequently seen as an employment choice for young people, one to get them started in employment, but is not seen as a career choice.
In North America and other parts of the world, the title of barista has been in long use, especially in Italian-style cafes and coffeehouses.
Home espresso coffee machines have also increased in popularity with the general rise of interest in espresso coffee, and with the Internet and its use as a tool to spread information about this beverage around the world. Today, a wide range of high-quality home espresso coffee machines can be found in kitchen and appliance stores, online vendors, and department stores.
Espresso coffee machines can be semi-automatic, automatic, super automatic and manual type. In super automatic espresso machines, you just need to press one button and a super automatic grinds whole beans inside the machine, tamps down the grounds, brews a delectable shot, and holds the waste in an internal container for later disposal.
In semi automatic machines, although there is an electric pump that produces the appropriate pressure for brewing, they still require quite a bit of user control. These machines are available in 2 styles: semi-automatic, with which you start and stop the brewing process manually, and fully automatic, which have brewing buttons that can be programmed to yield a specific amount of espresso.
Manual espresso machines require more user control than either of the other two types of espresso machines. But with a manual espresso machine, you will have maximum control over the final product i.e. espresso coffee.