Components of an Espresso Machine

A number of parts work together in an espresso machine.Coffe maker image by robootb from Fotolia.com

Espresso machines date back to 1901 when Luigi Bezzera discovered a way to reduce the break time for his employees by brewing coffee quicker. The more modern machine we are familiar with today did not come about until 1947. A number of parts work together to push pressurized, heated water through very small coffee grounds to brew the ideal shot of espresso.

Portafilter/Group Head

The portafilter is the part of the espresso machine that you put the grounds in and "tamp" or press the grounds. "Portafilter" comes from "porta" which means portable and "filtro," meaning filter. The main part of the portafilter is called the body. You put the espresso grounds in the portafilter basket and then place it in the body. The standard basket for a double shot can hold 14 grams while the basket for a single shot holds 7 grams. A portafilter spring holds the basket in place. On the bottom of the portafilter is the spout. The type of spout depends on whether the basket is for a single or double shot. Once the entire portafilter is put together with the espresso grinds, you attach it to the group head. The group head controls the water as it comes into contact with the espresso.

The water reservoir holds water that is brought into the boiler. There is already hot water and steam in the boiler. Cold water flows into a small cylinder called a heat exchange, which is located inside the boiler. The steam and water that are already in the boiler heat the cooler water. This heated water then goes to the group head. The more steam that is built up in the boiler, the hotter the water supplied to the group head. A pump pushes the water through the group head as well as into the boiler.

Every espresso machine comes with a steam wand. Steam wands on larger, commercial machines move in all directions and are normally placed at the end of the machine. Steam wands on older machines may only move forward and back. Commercial espresso machines also normally have hot water wands. The steam wand is used to froth milk or steam drinks. It is usually operated by a knob, but some machines have a lever or a button. You must clean steam wands frequently.