Automated Machines: Also known as One-touch machines, offer fully prepared espresso drinks at the push of a button, eliminating the need to grind beans, prepare a portafilter, or steam milk.
Barista: An Italian term for a person behind the bar, describing a person experienced in preparing coffee and espresso style drinks.
Boiler: A component of an espresso machine that is responsible for heating and storing water at a precise temperature, consisting of an enclosure, a heating element, and a thermostat.
Crema: The creamy or frothy top of a well pulled shot of espresso.
Diffuser: A component of the group head that distributes water more evenly over the grounds.
Dual Boiler: A machine that has two boilers usually having one for steam and one for brewing coffee due to different temperature demands and allows for a higher capacity. Generally found in larger, professional machines at restaurants and cafes. Also, in high end semi-professional machines for serious home machine users.
E-61: An industry pioneering model of an external group head that helps stabilize espresso shot temperature. The E-61 style grouphead is used by many different brands.
Espresso drinks: Any beverage prepared with espresso shots, often accompanied by cream or milk such as in cappuccinos or lattes.
Group head: A component of a barista style espresso machine, that distributes the heated water from the boiler, evenly over the ground espresso in the portafilter.
Heat Exchanger: An espresso machine in which the system for brewing coffee is separate from the steam boiler but is indirectly heated by the boiler through an enclosed reservoir situated inside of the steam boiler. The advantage of this is temperature stability throughout the entire shot once the heat exchanger is purged. Second, the water used for brewing does not deplete the water in the steam boiler allowing for higher capacity from the machine without the need for a dual boiler.
Manual Machines: Also known as Barista style machines, where the user must have some experience or skill to prepare espresso style drinks.
One touch Machines: Another term for an automated espresso machine.
PID: A "proportional, integral, derivative" itself is a set of equations or algorithms used in many industrial control applications. The PID is a small electronic box that is a physical representation of these algorithms which allow for precise control of the temperature for brewing water and steam.
Portafilter: The device that contains the ground espresso in barista style machines, consisting of a handle, spout and basket that creates a seal between the portafilter and the group head, which is then pressurized with water.
Shot of espresso (single): Generally, refers to a 1 oz serving of espresso.
Thermal Stability: The ability of a machine to hold the water at a consistent temperature usually achieved by using a dual boiler and PID.
Whole Beans: Coffee beans that have been roasted but not ground. Beans are often stored in whole form which helps to preserve the freshness of the bean.