They are on movable carts on the sidewalk, in gas stations and vending machines, and now you can have an espresso coffee maker for your personal use at home. Available in many styles and colors, the price can vary from under $30 to several hundreds of dollars depending on the quality you are looking for.
Regardless of the size, espresso coffee makers all work on the same theory: forcing near-boiling water through finely ground coffee. It should take slightly less than 30 seconds to brew a single shot of espresso, about one and three quarters of an ounce, using an espresso coffee maker.
The difference between an espresso coffee maker and a regular coffee maker is that in a regular coffee maker, hot water is run through coffee grounds, which absorbs the flavor of the coffee and then enters a reservoir, or carafe. The heated water is usually pulled from a different reservoir from which the finished brew ends up. The coffee beans are coarse ground and can take from one minute to several minutes to brew a single cup.
How Beans Are Ground Controls Time
In an espresso coffee maker, the beans are finely ground, almost to the consistency of powdered sugar, and placed in a filter. Cold water is stored in a reservoir until the heating chamber is heated to the desired temperature. Water is then transferred into the heating chamber, which heats it to near boiling. This is accomplished either automatically or by use of a pump depending on the model espresso coffee maker being used.
The hot water is then forced through the grounds and into a cup, taking about 25 seconds to make a shot of espresso, depending on the grind of the beans. How fine the beans are ground can be adjusted to help control brewing time. The finer the grind, the longer it can take, but the water is forced through the grind at about 220 pounds per inch.
Some espresso coffee makers also have a steam wand to froth or boil milk for making various type of espresso. The same heating chamber used to heat the water can be tapped to allow steam to escape through a wand, which has been placed into a container of milk for heating or pressurized steam is blown across the top of the milk to create a froth to be added to the espresso.
There are even camping espresso coffee makers that obtain their heat from an open flame where water is heated in the bottom with the hot water rising through a tube running from the bottom reservoir, through the finely ground beans, and into a separate reservoir. Although they do produce espresso, the water is not forced through as quickly.