3-way solenoid – an electrically controlled valve (electrovalve) used to control the flow of water to and from an espresso machine group head. Before extraction the solenoid will prevent water flowing to the grouphead; once extraction is activated water is allowed to flow from the boiler to the grouphead; after completion of the extraction cycle, the solenoid diverts excess water and pressure away from the grouphead to allow safe removal of the portafilter.

7 grams – the standard measure of ground coffee used to make a single espresso shot; however some coffee suppliers may recomment 8 or 9 grams per single espresso shot.

9 bar – the ideal pressure for extracting espresso.   High quality commercial and home espresso machines will extract espresso at 8-10 bar

14 grams – the standard measure of ground coffee used to make a double shot of espresso; however some coffee suppliers may recomment 16 to 18 grams per double shot of espresso.

15 bar pump - the rated operating pressure of most consumer and prosumer espresso machines.   One of the most common vibration pumps used for consumer, prosumer, and office espresso machines is the ULKA pump rated at 15 bar max pressure.

Anglophiles – a term used to describe residents of those countries whose primary language is English; this includes, but is not limited to England, Ireland, Scotland, Whales, United States of America, Canada, Australia, South Africa, and New Zealand.

Arabica – one of the two main species (the other is Robusta) of cultivated coffee plans.

Aroma – the smell that is a key characteristic of hot, freshly brewed coffee. Aroma is one of the main sensory characteristics used to describe coffee.

Back flush – a process used to clean the shower screen, grouphead, and 3-way valve on a commercial espresso machine and some domestic espresso machines.

Bar – a unit for measuring pressure.   1 Bar is equal to 100 kilopascals (kPa). Espresso machines extract espresso shots at approximately 9Bar of water pressure, steam boilers operate at approximately 1 Bar of steam pressure.

Barista – the Italian word used to describe someone whose profession is to prepare beverages. In Italian culture the term is used to describe professionals who prepare alcoholic beverages as well as hot drinks. Anglophiles have adopted the term Barista to refer to someone who prepares espresso based drinks.

Blade Grinder – an appliance used to grind herbs and spices by rotating blades “chopping” the contents. Blade grinders are not suited to preparing coffee for espresso based drinks as they produce an inconsistent particle size.

Blend – a mixture of two or more single-origin coffees.

Blending – the craft/science of mixing two or more coffee beans/roasts to achieve a particular coffee with particular characteristics. Roasters will use blending techniques to achieve certain characteristics in flavour, ease of brewing, aging, and aroma.

Body – the sensation of richness, thickness, and complexity when tasting a cup of coffee. Body is one of the main sensory characteristics used to describe coffee.

Café au Lait – a French coffee beverage; literally translated as “coffee with milk”. Café au Lait typically consists of one-third strong drip coffee topped with two thirds steamed milk. 

Caffeine – a mild stimulant that occurs naturally in coffee and tea.

Coffee Roaster - a machine used to roast green coffee beans to produce brown “roasted” coffee. Coffee Roaster can also refer to a company/individual involved in the operation of roasting coffee.

Decaf – decaffeinated Coffee

Decaffeination process – a process where the caffeine is removed from the coffee beans by one of four key methods.

Degassing – the process undertaken after roasting, where freshly roasted beans release carbon dioxide gas (CO2).

Demitasse – French for “half cup” – is a small cup used to serve espresso.   Demitasse cups are typicall no larger than 90ml and are typically made of ceramic or glass.

Doppio – Italian word for double, usually refers to a double espresso

Doser – a device used to “dose” a single shot of ground coffee. Dosers are typically found on the front of specialist espresso coffee grinders. Dosers typically dispense coffee via a spring loaded mechanism that rotates pie segments within the doser. Each pie segment is equal to one shot “dose” of coffee. On commercial espresso coffee grinders the dose is often adjustable. Correct operation of a dosing grinder is to dose for a single or double shot with either one or two clicks respectively of the dosing handle.

Electrovalvola – Italian for electrovalve

Electrovalve – Electrically controlled valve typically used in espresso machines for controlling the flow of water to and from the boiler.

Extraction time – the time taken from when water begins to flow through the coffee puck until the flow of water stops.

Fairtrade – a set of standards used to govern the trade of products. Fairtrade is the trademark of the Fairtrade Labelling Organizations International, who sets the standards and administers certification. There are two types of standards, generic standards and product specific standards. A product displaying the Fairtrade trademark is deemed to have met the standards prescribed for that product.

Filter holder – another name for a portafilter.

Hard Water – is water containing high levels of mineral elements. Hard water elements typically consist of calcium and magnesium. In espresso machines hard water will typically cause accelerated buildup of scale buildup throughout the espresso machine.

Heat exchanger – a mechanical device used to transfer heat from one mass to another, often heat exchangers are used to transfer heat to (or away from) a body of liquid or gas. In an espresso machine a heat exchanger is used to exchange heat from a steam boiler to heat fresh (tap temperature) water to 92 degrees for use in the production of espresso.

Hopper – the part of the coffee grinder that holds whole beans. The hopper is typically constructed of transparent plastic.

Housing – a fabricated structure used to house a mechanical device. On an espresso machine the housing is the external shell that seals the boiler and electronics from the user. The housing is often constructed of metal, but may be constructed of plastic.

La Pavoni – One of the oldest manufacturers of espresso machines. In 1905 Pavoni developed the first commercial espresso machine.

Latte – Italian word for milk, often incorrectly used to refer to a café latte.

Lungo – Italian word for long, a long black can often be referred to as a Longo

Moka Pot – a stove top coffee maker where heated water is forced through coffee into an upper chamber.

Nero – Italian word for black

O-ring – a seal with a circular cross section used to create a pressure resistant seal between two surfaces. In espresso machines o-rings are typically constructed of food grade rubber type compounds.

Pull – a term used to refer to a producing a shot (or two) of espresso. The term “pulling a shot” refers to the act of using a lever espresso machine to pull the lever to pump water through the coffee.

Roaster – a machine used to roast green coffee beans to produce brown “roasted” coffee. Roaster can also refer to a company/individual involved in the operation of roasting coffee.

Skinny – a term used to refer to an espresso based drink using trim or reduced fat milk.

Soy – a term used to refer to a beverage where soy milk has been substituted for regular dairy milk.

Soy milk – a man made product created through the processing of soy beans.

Staling – a colloquial expression used to describe the oxidation process that leads to coffee becoming stale.

Thermometer – a device used to measure temperature. A barista may use a thermometer to monitor the temperature of milk as it is steamed.

Thermostat – a switch used to control the temperature of a particular device or mass. In espresso machines a thermostat may be used to control the temperature of water in a boiler.

Touchpad – a thin membrane containing one or more switches that are activated by press.

Under extraction – refers to a shot of coffee that is extracted with not enough pressure or water.   Under extraction is the opposite of over extraction.   An under extracted shot will often be weak and watery with little or no crema.   You should throw away an under extracted shot.

Venti – Italian for twenty. Used to refer to a twenty fluid ounce (590mL) beverage at some large coffee chain stores.

Water Softener – a water filtration system designed to remove hard water elements from the water, thus making the water “softer”. Water softeners are typically fitted to commercial espresso machines in areas where the water contains sufficient mineral deposits.