omaneo — Espresso glossary

Espresso glossary

From Acidity to Yield: the most important terms around espresso, grinder and milk, explained briefly. Type a term or jump to a letter.

148 terms

0–9

9 bar: Classic reference brew pressure for espresso extraction.

A

Acidity (sourness): Perceptible, often fruity acidity in coffee; contributes to aromatic complexity.
Aeropress: Brewing method that extracts coffee by immersion and pressing; produces a clear, aromatic coffee.
Affogato: Italian dessert of a scoop of vanilla ice cream topped with hot espresso.
Allongé: Espresso lengthened with hot water that retains more crema than an Americano.
Altitude (growing altitude): Height of the growing region above sea level; higher altitudes usually yield denser, more aromatic beans.
Americano: Espresso lengthened with hot water, making it milder yet still aromatic.
Arabica: High-quality coffee variety from the highlands; considered aromatic, mild and acidity-forward.
Aroma-protection valve: One-way valve on the bean bag that lets CO₂ escape but lets no oxygen in.

B

Backflush (back-flushing): Cleaning the group head with a blind basket and cleaning powder by flushing water backwards.
Barista: Professional who prepares espresso and specialty coffee drinks, often skilled in latte art.
Basket: Filter basket inserted in the portafilter that holds the ground coffee; for single or double shots depending on size.
Bean-to-cup machine: Machine that handles grinding, tamping and brewing fully automatically in one appliance.
Bitter compounds: Natural component of coffee, responsible for bitterness and depth of flavour.
Blend: Mixture of different coffee varieties or bean batches for a balanced flavour profile.
Blind basket: Closed basket without holes for back-flushing and cleaning the group head.
Blooming: Initial swelling of freshly ground coffee on contact with water as CO₂ escapes.
Body: Perceived density and fullness of the coffee in the mouth.
Boiler: Water vessel in the espresso machine in which the water for brewing and steam is heated.
Bottomless portafilter: Portafilter without a spout (naked); allows a precise assessment of the extraction.
Bottomless Portafilter: English term for the bottomless portafilter without a spout.
Brew pressure: Pressure with which water is forced through the ground coffee; ideally around 9 bar.
Brew ratio (ratio): Ratio of ground coffee used to espresso output, e.g. 1:2.
Brew temperature: Temperature of the brewing water during extraction; ideally about 90–96 °C.
Burr: English term for the grinding disc/cone; flat burr = disc grinder, conical burr = conical grinder.
Burr set: Part of the grinder that crushes the beans; usually a flat or conical burr set.

C

Café crème: Mild coffee brewed from the portafilter with a coarse grind and more water (Schümli).
Caffè latte (latte): Espresso with plenty of hot milk and little foam; milder than a cappuccino.
Cappuccino: Espresso with frothed milk, classically in roughly equal parts espresso, milk and foam.
Capsule machine: Machine that prepares coffee from portioned capsules.
Channeling: English term for channel formation; uneven flow through the puck.
Channeling (channel formation): Uneven flow through the puck; water finds channels and leads to flawed extraction.
Cold brew: Cold-extracted coffee that steeps in cold water for many hours; mild and low in acidity.
Conical burr grinder: Grinder with a conical burr; works more slowly and runs cooler than a flat burr grinder.
Cooling flush: Brief release of water on E61 machines to bring overheated brewing water down to the target temperature.
Cortado: Espresso with a small amount of lightly frothed milk in a ratio of about 1:1.
Crema: Golden-brown layer of foam on the espresso; a sign of freshness and correct extraction.
Cupping: Standardised tasting method for assessing the aroma, acidity and body of a coffee.

D

Dead space: Residual ground coffee left in the grinder between the burrs and the chute.
Degassing (outgassing): Release of CO₂ from freshly roasted beans; fresh roast needs a few days of resting time.
Descaling: Removing limescale deposits from the boiler and pipes to keep the machine in good condition.
Dialing in: Adjusting grind size, dose and time until the espresso extracts optimally.
Direct trade: Direct trade between roaster and coffee farmer without intermediaries; often higher quality and fair prices.
Distributor: Tool that levels the ground coffee evenly in the portafilter before tamping.
Doppio: Double espresso, pulled from a double basket.
Dose / dosing: Weighed amount of ground coffee per shot, or the act of dosing that amount.
Dosing funnel: Attachment on the portafilter that prevents ground coffee from spilling during grinding.
Double spout: Portafilter with two spouts for filling two cups at the same time.
Drip coffee: English term for filter coffee, where water drips through a filter bed.
Drip tray: Tray under the group head that collects excess water and drips.
Dual boiler: Machine with two separate boilers for brewing water and steam; enables constant temperatures.
Dual-circuit machine: Machine with a boiler and a heat exchanger; allows brewing and frothing at the same time.

E

E61 group head: Thermosiphon-heated group head developed in 1961; a classic with integrated pre-infusion.
Espresso: Concentrated coffee drink extracted from finely ground coffee under high pressure.
Espresso machine: Appliance that forces hot water under pressure through ground coffee to make espresso.
Espresso shot (shot): Single portion of espresso from the portafilter; single shot or double shot.
Extraction: Process in which flavours and compounds pass from the ground coffee into the water.
Extraction time: Duration of the water flow through the puck; typically 25–30 seconds for espresso.

F

Fair trade: Certified fair trade that secures minimum prices and better conditions for coffee farmers.
Flat burr grinder: Grinder with two parallel grinding discs; produces an even grind.
Flat white: Espresso drink with plenty of fine-textured microfoam milk; creamier and more coffee-forward than a cappuccino.
Flow profiling: Controlling the flow rate during the shot to deliberately influence the extraction.
Flow rate: Speed at which the espresso flows through the puck; influences the extraction.
French press: Brewing method with a coarse grind in which coffee steeps in water and is pressed through a mesh.
Frothing: Heating and frothing milk with the steam wand to produce microfoam.

G

Grind size: Fineness of the ground coffee; fine for espresso, medium for filter, coarse for French press.
Grinder: English term for the coffee grinder.
Group head: Component where water meets the ground coffee and the espresso is extracted.
Group head: English term for the group head.
Group head gasket: Sealing ring between the group head and the portafilter that seals the brewing process; wear part.
Growing regions: Regions where coffee is grown; they influence the flavour, quality and character of the bean.

H

Harvest season: Time of the coffee harvest; varies by region and altitude and determines quality.
Headspace: Distance between the puck surface and the shower screen; influences even wetting.
Heat exchanger: Tube running through the boiler that heats the brewing water and allows steaming and brewing at the same time.
Honey process: Processing in which some of the fruit pulp stays on the bean; yields sweet flavours.

K

Knock box: See knock box; container for knocking out the coffee puck.
Knock box: English term for the knock box.
Knock box (Knockbox): Container with a rubber bar for knocking the spent coffee puck out of the portafilter.
Knocking out: Removing the extracted coffee puck from the portafilter with a knocker or knock box.

L

Latte art: Pattern in the milk foam created when pouring the frothed milk into the espresso.
Latte macchiato: Drink of hot milk, milk foam and espresso, classically served in layers.
Leveler: Tool for smoothing and levelling the ground coffee before tamping.
Lever machine: Espresso machine in which the pressure is generated manually by a piston lever.
Lever machine: English term for the lever machine.
Long black: Espresso pulled over hot water; preserves the crema (AU/NZ).
Lungo: Lengthened espresso pulled with more water and a longer time.

M

Macchiato (espresso macchiato): Espresso "stained" with a small dollop of milk foam.
Microfoam: Fine-textured, velvety milk foam needed for latte art and creamy drinks.
Milk jug (pitcher): Stainless-steel jug with a spout for frothing and pouring milk.

N

Naked portafilter: English term for the bottomless portafilter.
Naked Portafilter: English term for the bottomless portafilter.
Naturals (dry processing): Processing in which the coffee cherry is dried with its pulp; often fruity in flavour.

O

Over-extraction: Extraction that is too long or too fine; makes the espresso bitter and harsh.

P

Piccolo (piccolo latte): Small milky coffee made from ristretto/espresso and a little milk in a small glass.
PID: Electronic temperature control that keeps the brew temperature precisely constant.
Pod machine: Machine that prepares coffee from pre-portioned soft pods.
Portafilter: Removable handle with a filter basket into which the ground coffee is filled and tamped.
Pour over: Hand-poured brewing method in which water is poured over the ground coffee by hand.
Pre-infusion: Pre-wetting the coffee puck with a little water at low pressure before the actual extraction.
Pre-infusion: English term for pre-infusion; pre-wetting the puck at low pressure.
Pressure gauge: Pressure display on the machine for monitoring boiler or brew pressure.
Pressure profiling: Deliberately varying the brew pressure during the shot for individual flavour profiles.
Pressurestat: Pressure switch that automatically regulates the heating in the boiler via the steam pressure.
Puck: The compressed, round cake of ground coffee in the portafilter.
Pull a shot: English expression for pulling an espresso.
Purge: Briefly releasing water or steam to stabilise the temperature or clean the nozzle before use.

R

Refractometer: Measuring device for determining the proportion of dissolved solids (TDS) in coffee.
Ristretto: Very short, concentrated espresso pulled with less water.
Roast level: Degree to which the beans are roasted, from light to dark; determines aroma, acidity and bitterness.
Roast (roasting): English term for Röstung; light/medium/dark roast denote the roast level.
Robusta: Strong, caffeine-rich coffee variety; yields more crema and a harsher flavour.
Rolling phase: Second phase of frothing, in which the milk circulates beneath the surface and the foam is refined.
Rotary pump: Pump with constant pressure; quieter and more precise, especially in commercial machines.

S

Scale (espresso scale): Precision scale for exactly weighing ground coffee and espresso output for reproducible shots.
Schümli: Swiss term for a café crème with fine crema.
Shot (extraction): The process of making espresso; the start of water flowing through the ground coffee.
Shower screen: English term for the shower screen in the group head.
Shower screen (brew screen): Perforated screen in the group head that distributes the water evenly over the puck.
Single-circuit machine: Machine with one boiler for brewing and steam; brewing and frothing at the same time is not possible.
Single dose: Grinding method in which exactly the amount of beans needed is freshly ground for each shot.
Single origin: Coffee from a single origin (country, region or farm) rather than a blend.
Single shot / double shot: Single or double espresso shot from the corresponding basket.
Solenoid valve: Electrically controlled valve that regulates the water flow in the machine; relieves the pressure on the puck after the shot.
Solenoid valve: English term for the solenoid valve; relieves the pressure on the puck after the shot.
Spout: Outlet on the portafilter through which the espresso flows into the cup.
Steam wand: Nozzle of the espresso machine through which hot steam escapes to froth the milk.
Steam wand: English term for the steam wand.
Steaming: English term for frothing and heating milk with the steam wand.
Stovetop espresso maker (moka pot): Stovetop pot that forces coffee through the grounds with steam pressure; espresso-like, but without high pressure.
Stretching phase: First phase of frothing, in which volume is created by drawing air in at the surface.

T

Tamper: Tool with which the ground coffee is evenly pressed in the portafilter.
Tamping: Evenly pressing the ground coffee in the portafilter with the tamper.
Tamping: English term for tamping; pressing the ground coffee in the portafilter.
Tamping mat: Non-slip rubber mat that protects the work surface and the portafilter rim during tamping.
Tamping pressure: Force with which the ground coffee is compressed in the portafilter; important for even extraction.
Tamping station: Stand that holds the portafilter in place and keeps it straight during tamping.
TDS (total dissolved solids): Proportion of dissolved solids in the coffee; a measure of extraction strength.
Terroir: All the site factors (soil, climate, altitude) that shape the character of the coffee.
Thermoblock: Fast-heating system with a tube coil in a heating block instead of a boiler.

U

Under-extraction: Extraction that is too short or too coarse; makes the espresso sour and watery.
Updosing: Increasing the amount of ground coffee in the basket beyond the standard dose.

V

Vibration pump: Pump with an oscillating piston; louder and less constant, typical of household appliances.
VST basket: High-precision, laser-measured filter basket for particularly even extraction.

W

Washed (washed processing): Processing in which the pulp is removed and the bean is fermented and washed; clean flavour.
Water hardness: Limescale content of the water; influences flavour and scaling of the machine.
Water tank: Container that supplies the espresso machine with fresh water.
WDT tool: Weiss Distribution Technique: fine needles for loosening the ground coffee against clumps and channeling.

Y

Yield: Amount of espresso extracted, or the proportion of substances dissolved from the ground coffee (extraction yield).

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