Everything we know about coffee gear

Bar mat

A rubber mat that lives on the bar under the group to catch drips and spills.

Cleaning brush

A brush with stiff natural or nylon bristles used to clean the group head, shower screen, and grinder.

Coffee canister (airtight container)

A sealed container (often with a valve or vacuum system) for storing roasted beans.

Coffee scale (barista scale)

A precision scale, typically 0.1g resolution, designed specifically for coffee work — waterproof, fast response, with integrated timer.

Cup warmer

An electric plate or passive warmer for pre-heating cups.

Dechunker (bean-density declumper)

A pop-up screen or sieve that mechanically breaks grind clumps. Sometimes integrated into dosing cups.

Dosing ring

A magnetic or friction ring that sits on top of the basket to catch loose grounds and guide them in.

Glass carafe / server

A container for decanting brewed coffee — common with pour-overs, Chemex (integrated), and batch brewers.

Gooseneck kettle

A kettle with a long, thin, curved spout that delivers a precise, controllable water stream.

Group brush

A specific shape of brush with an angled head designed to reach the shower screen while the portafilter is removed.

Knob & Handle

Wood, metal, or plastic grips for steam taps and portafilters — wear items that get burned, dropped, and replaced as much for looks as for function.

Knock box

A receptacle (often with a rubber bar) for knocking spent pucks out of the portafilter.

Knock tube

A tall cylindrical version of a knock box, often used on bar tops where width is limited.

Latte art pen

A small tool like a dull skewer used for etching details in latte art.

Levelling distributor

A spinning tool with angled blades that flattens the grind bed before tamping.

Milk thermometer

An analogue or clip-on thermometer that sits in the milk jug to show steaming temperature.

Palm tamper

A non-handled tamper shaped to sit in the palm and use body weight rather than arm strength.

Portafilter stand

A cradle or holder that keeps the portafilter level during dosing.

Puck rake

A small manual tool with fingers that reach into the basket to break up clumps before tamping — an alternative to WDT.

Shot timer

A stopwatch — usually integrated into a scale or a standalone unit — that times espresso extraction.

Tamper

Tool used to compress the coffee puck evenly in the basket before brewing.

Tamping mat

A rubber or silicone mat that cushions the portafilter during tamping and prevents bench damage.

WDT tool

A handle holding 4–8 fine needles (acupuncture needles, 0.3–0.4mm) used to stir the grounds in the basket.

Anti-Vacuum Valve

One-way valve that lets air into the boiler as it cools to prevent vacuum collapse and pull-back of water.

Boiler

Pressurised vessel that heats water for brewing, steaming, or both.

Boiler material (copper, stainless steel, brass)

The metal the boiler is built from. Copper is traditional and thermally efficient; stainless steel is inert and doesn't need descaling as often; brass is used for heat exchangers and some commercial boilers.

Brew boiler

The smaller, lower-temperature boiler that produces water for espresso extraction — typically held at 90–96 °C.

Cooling flush

Running water from the group on an HX machine (with no portafilter engaged) to purge steam-heated brew-line water before pulling a shot.

Dual boiler

A machine with two completely separate boilers — one for brewing, one for steaming — each with its own element and thermostat/PID.

Group head temperature

The actual water temperature delivered to the coffee puck, which is always slightly different from boiler temperature.

Heat exchanger (HX)

A copper tube running through the steam boiler — brew water flows through it on demand and is heated by surrounding boiler water.

Heating Element

Resistive coil that converts electricity into heat inside the boiler — usually a sheathed nichrome element bolted to the boiler flange.

Heating Element Gasket

Sealing washer between the heating element flange and the boiler — the slow drip behind the panels is almost always this gasket.

Insulation jacket

A foam or foil wrap around the boiler to reduce heat loss.

Offset (temperature offset)

The calibration value entered into a PID to correct for the difference between the sensor reading (usually in the boiler) and actual water temperature at the group.

PID Controller

Electronic temperature controller that holds boiler temp to ±0.5 °C by reading a probe and pulsing the element via a relay or SSR.

PID tuning

The process of setting the P, I and D values in a PID controller to minimise temperature overshoot and settling time for a specific boiler.

Pressure Relief Valve (Safety Valve)

Spring-loaded boiler safety valve that vents steam if pressure runs away — the last line of defence against a boiler rupture.

Pressurestat

Mechanical pressure switch that turns the heating element on and off to hold the steam boiler at a set pressure — the analogue ancestor of the PID.

Pressurestat (pstat)

Mechanical pressure switch that cycles the steam boiler element on and off to hold a set pressure — typically 1.0–1.5 bar.

Probe (Level / Temperature)

Stainless rod or thermocouple that tells the controller how full or how hot the boiler is — fouled probes cause overfilling, dry-fires, and runaway PIDs.

Single boiler

A machine with one boiler that is switched between brewing temperature (~93°C) and steaming temperature (~125°C).

Steam boiler

The larger boiler that produces steam for milk texturing and hot water for tea — typically held at 120–130 °C and 1.0–1.5 bar.

Switch (Power, Brew, Steam)

Mechanical rocker or push-switch on the front panel — handles the on/off, brew, and steam selections. They wear out after a few hundred thousand cycles.

Temperature stability

The consistency of brew water temperature within a shot and across back-to-back shots.

Thermal fuse

A safety device that permanently breaks the circuit if the boiler overheats (e.g., from a failed thermostat or dry-boil condition).

Thermoblock

A small aluminium or stainless steel block with a water channel and a heating element that heats water on-demand, millilitres at a time.

Thermocoil

Breville's proprietary thermoblock design — a stainless steel coil wrapped around a heating element, giving better temperature control than a basic thermoblock while still being fast to heat up.

Thermostat

Mechanical bimetallic switch that opens or closes a circuit at a set temperature — used for boiler control on simpler machines and as a safety cutout on all machines.

AeroPress

A plastic plunger brewer invented by Alan Adler in 2005. Uses air pressure to force water through a paper filter into the cup.

AeroPress bypass

Adding water after brewing to dilute to desired strength.

AeroPress inverted method

Starting with the AeroPress upside-down so no water drips out during steep time, then flipping and plunging.

AeroPress standard method

The traditional technique — plunger in filter, coffee in chamber, brew, plunge.

Batch brew

Automated drip coffee — a machine heats water to temperature and delivers it over a larger bed of coffee (usually 500ml–2L).

Chemex

A glass pour-over brewer with a built-in filter holder and very thick paper filters, invented in 1941.

Clever Dripper

A V60-shaped dripper with a valve at the bottom that holds water until the brewer is placed on a cup.

Cloth filter

A reusable fabric filter used on siphons and some pour-overs.

Cold brew

Coffee steeped in cold or room-temperature water for 8–24 hours, producing a smooth, low-acid concentrate.

Cold drip

A slow cold extraction where ice-cold water drips one drop at a time through a column of grounds over 3–12 hours.

French press (plunger)

An immersion brewer with a metal mesh plunger that separates grounds from coffee.

Hario Switch

A V60 with a valve, similar concept to the Clever but the V60 shape.

Immersion vs percolation

Immersion = grounds sit in water for the full brew time (plunger, Clever, AeroPress). Percolation = water flows through grounds in one pass (V60, Chemex, espresso).

Japanese iced

Pour-over brewing directly over ice, cooling the coffee immediately while preserving its aromatics.

Kalita Wave

A flat-bottomed pour-over dripper with three small holes, using a wavy-ridged paper filter.

Melitta

The original pour-over dripper, invented by Melitta Bentz in 1908 — a trapezoid shape with a flat bottom and single hole.

Metal filter

A reusable fine-mesh metal filter.

Moka pot (stovetop)

An aluminium or stainless pressurised brewer invented by Alfonso Bialetti in 1933, producing strong, concentrated coffee on the stovetop.

Paper filter (bleached vs natural)

Paper discs, cones or wedges that separate coffee grounds from the brew.

Pour-over

Any method where hot water is poured in a controlled manner over grounds in a filter cone.

Siphon (vacuum pot)

A two-chamber vacuum brewer where steam forces water up into the grounds chamber, then cools and draws brewed coffee back through a filter.

Turkish (cezve)

Very finely ground coffee boiled with water (and often sugar) in a small long-handled pot, served unfiltered.

V60

A conical pour-over dripper invented by Hario, with spiral ridges and a single large hole at the bottom.

ACCC consumer guarantees

The Australian Consumer Law (ACL) that entitles buyers to a product that is of acceptable quality, fit for purpose, and matches its description.

ASCA (Australian Specialty Coffee Association)

The Australian affiliate of the Specialty Coffee Association, running national barista, latte art, cup tasters and brewers cup championships.

Barista champion credentials

Titles awarded at official competitions run by the World Coffee Events (WCE) global body and affiliates like ASCA (Australian Specialty Coffee Association).

CE

Conformité Européenne — the European regulatory mark for electrical and pressure equipment.

Energy rating

An efficiency rating — standby power draw, warm-up time, heat retention.

NSF

An American food-safety and public-health certification body.

PED (Pressure Equipment Directive)

The European Union directive covering pressure vessels like steam boilers.

RCM / C-Tick

The Regulatory Compliance Mark — Australia and New Zealand's electrical safety and EMC certification, previously called C-Tick.

SCA certification

Training certifications from the Specialty Coffee Association — Barista Skills, Brewing, Sensory, Roasting and Green Coffee, each at Foundation, Intermediate and Professional levels.

WaterMark

The Australian regulatory certification (administered by the ABCB) for plumbing products connecting to drinking water systems.

World Barista Championship (WBC)

The global annual barista competition where competitors present one of each — espresso, milk drink, signature drink — scored by sensory judges.

Anaerobic processing

Fermenting cherries in sealed tanks to develop experimental flavours.

Arabica

Coffea arabica — the higher-quality, lower-caffeine coffee species responsible for nearly all specialty coffee.

Blend

Coffee mixing beans from multiple origins for a consistent, designed flavour profile.

Carbonic maceration

A processing method borrowed from winemaking where whole cherries ferment in CO₂-rich tanks.

Cupping

The standardised protocol for evaluating coffee — grounds steeped in hot water, crust broken, slurped from spoons, scored on a 100-point scale.

Degassing

The release of CO₂ from beans in the days following roasting.

Development time ratio (DTR)

The percentage of the roast spent between first crack and drop.

First crack

The audible popping sound that happens early in roasting, as water escapes bean cell walls.

Green bean

Unroasted coffee.

One-way valve (degassing valve)

A small valve in a coffee bag that lets CO₂ escape without letting oxygen in.

Processing (washed, natural, honey)

How the coffee cherry is prepared to become green bean. Washed = fruit removed before drying (clean, acidic). Natural = dried with fruit on (fruity, heavier body). Honey = partially fruited (in-between).

Q Grader

A certified coffee quality evaluator, qualified through a rigorous SCA/CQI exam.

Roast date

The date the beans came out of the roaster.

Roast level (light, medium, dark, Italian)

How long and hot coffee is roasted. Light = short time (Scandinavian/specialty). Medium = most commercial. Dark = longer (Italian-style). Italian = very dark, oily surface.

Robusta

Coffea canephora — a hardier species with roughly 2× the caffeine of Arabica, more body, heavier crema, and harsher flavour.

SCA (Specialty Coffee Association)

The global body that sets standards for specialty coffee — brewing, cupping, water quality, barista skills.

Second crack

A later, quieter cracking phase as bean cell walls break down under heat.

Single origin

Coffee from a single farm, region, or country — bottled without blending.

Specialty coffee

Coffee scoring 80+ points on the SCA 100-point scale, produced with attention to quality from farm to cup.

Third wave

The movement (started in the 2000s) treating coffee as a craft product like wine, with emphasis on origin, variety, roast, and brew method.

Varietal

The specific genetic variety of Arabica — e.g., Bourbon, Typica, Geisha (Gesha), SL28, SL34, Pacamara, Caturra, Catuai.

Affogato

A scoop of vanilla ice cream or gelato with a shot of hot espresso poured over.

Americano

Espresso with hot water added after. Originated with US servicemen in WWII Italy who found espresso too strong.

Cappuccino

A double shot with steamed milk topped with a thick foam layer (traditionally 1/3 espresso, 1/3 milk, 1/3 foam), dusted with chocolate powder in Australia.

Cortado

Espresso with equal parts lightly-textured warm milk. Spanish origin. Usually served in a 150ml Gibraltar glass.

Espresso (short black)

A 30–40ml double shot of espresso, served on its own in a demitasse.

Flat white

A double shot of espresso with 140–160ml of finely textured milk, usually served at 165ml volume. Australian-New Zealand origin, debated between the two.

Iced latte

Espresso + cold milk + ice.

Iced long black

A double shot poured over cold water and ice.

Latte (café latte)

A double shot with 200–240ml steamed milk, served in a glass.

Long black

A double shot poured over 120–160ml of hot water. The Australian/NZ alternative to an Americano.

Lungo

A long shot — 1:2.5 to 1:3 ratio, producing a weaker, more voluminous drink.

Macchiato (traditional vs Australian)

Traditional Italian macchiato = espresso "marked" with a small dollop of foam. Australian macchiato = often a short-sized latte with a small amount of milk, often served in glass.

Mocha

Espresso, steamed milk and chocolate (syrup or powder). In Australia, often served with whipped cream and chocolate powder on top.

Piccolo latte

An Australian/NZ invention — an espresso topped up with steamed milk in a 90ml glass. Essentially a smaller, coffee-forward latte.

Ristretto

A short, concentrated shot — 1:1 to 1:1.5 ratio, typically 18g in, 18–27g out.

Error codes

Machine-specific fault codes (e.g., E01, E05, F2) displayed on the screen.

Fast shot

Extraction runs much faster than expected.

Grinder making metallic screech

High-pitched metal-on-metal sound from the grinder.

Grinder motor hum but no grind

Grinder turns on but burrs don't rotate.

Inconsistent shot times

Same dose, same grind, same machine — different shot times every pull.

Leaks from boiler

Water pooling underneath the machine.

Leaks from group

Water escapes around the portafilter during brewing.

No power

Machine completely dead — no lights, no pump.

No pressure

Pump runs, water flows, but pressure gauge shows nothing or very little.

Not heating

Machine turns on but never gets hot enough to brew or steam.

Over-pressure

Pump pressure climbs above 12 bar and stays there.

Portafilter sneezing

A puff of coffee grounds ejecting from the portafilter when unlocked after a shot.

Pump noise / cavitation

Loud rattling, screaming, or uneven sound from the pump.

Pump won't prime

Pump runs but no water reaches the group.

Scale blockage

Restricted flow or intermittent fault caused by calcium carbonate buildup in boiler, pipes, or solenoid.

Slow shot

Extraction runs much slower than expected, or the machine struggles to produce flow.

Solenoid stuck

The 3-way solenoid fails to open (no brew) or fails to close (constant drip, no pressure release).

Soupy / watery puck

The puck doesn't knock out as a solid cake — comes out as slurry.

Spurting / geysering

Water erupting from the shower screen or brew path, often with a gurgling sound.

Steam wand blocked

Little to no steam flow, or uneven spray from the tip.

Three-way solenoid dripping

A slow drip from the group after a shot ends, indicating the solenoid isn't sealing properly.

Vacuum breaker stuck

The small valve that vents boiler air on startup fails to close, causing continuous steam escape from the top of the boiler.

Weak steam

Steam pressure feels anaemic — foam is slow or impossible to build.

3-way solenoid valve

An electromechanical valve that directs water from the pump to the group during extraction, then releases puck pressure to the drip tray when the shot ends.

Bottomless (naked) portafilter

A portafilter with the spouts and bottom removed, exposing the basket and the underside of the puck during extraction.

Check valve (non-return valve)

A one-way valve that prevents water flowing backwards through the system.

Dispersion block (diffuser)

The metal plate above the shower screen that spreads water from the group inlet evenly across the coffee puck.

Dispersion Plate / Block

The thicker plate above the shower screen that distributes incoming water before it reaches the screen.

Drip Tray & Drain

The catch tray under the group plus the drain hose that takes waste water from the 3-way solenoid and the drip tray to the bin or floor waste.

E61 Group

The classic Faema E61 brew group — a thermosiphon-fed cast brass group with built-in pre-infusion and a 3-way valve, found on most prosumer HX machines.

E61 group head

A chrome-plated brass brew group originally designed by Faema in 1961, featuring a thermosyphon loop that circulates water from the boiler through the group to keep it at brew temperature. Identified by its distinctive mushroom shape and three-position lever.

Filter basket

The perforated metal cup inside the portafilter that holds the ground coffee. Specified by diameter (49–58mm), dose (7g single, 14–22g double, 20–25g triple), and hole pattern.

Flow control device (FCD, flow profiler)

A needle-valve mounted in the group head that lets the barista throttle water flow during a shot — enables flow profiling on E61 and lever machines.

Flow restrictor

Any component (gicleur, orifice, or valve) that restricts water flow into the group, usually to generate gentler pre-infusion.

Gicleur

A small brass jet (typically 0.6–0.8 mm) that meters water flow into the group — limits pressure ramp and brew flow.

Gicleur (jet)

A small brass jet (typically 0.6–0.8 mm) that meters water flow into the group — limits pressure ramp and brew flow.

Group Gasket

Rubber seal between the portafilter and the group head — the part that goes hard, leaks, and stops you from locking in straight.

Group gasket (portafilter gasket)

Rubber ring sealing the portafilter against the group head — wears flat and leaks; a 6-monthly service item.

Group Head

The brass assembly where the portafilter locks in and brewing happens.

IMS screen / competition screen

A precision-etched shower screen (or basket) made by IMS in Italy, with laser-drilled holes and tighter tolerances than stock stamped screens. The "Competition" line is used by most World Barista Championship competitors.

Lever group

A manually operated brew group where the barista uses a lever to generate extraction pressure, either via a spring (spring-lever) or by pressing directly on the water column (manual piston / dipper).

Mushroom (E61)

The internal brass piston in an E61 group that the cam pushes — controls inlet flow and exhaust to the drip tray.

OPV (over-pressure valve)

Spring-loaded valve that caps brew pressure at a set point (typically 9–10 bar) by venting excess pump output back to the reservoir.

Paddle (brew paddle)

A lever-style flow control built into the group on machines like the Slayer, Kees van der Westen Speedster and La Marzocco Strada MP.

Portafilter

Detachable handle that holds the basket and locks into the group head — the part you tamp into and lock up to brew a shot.

Portafilter spring (basket retaining clip)

The C-shaped wire clip inside the portafilter that grips the basket and stops it falling out when you knock the puck.

Pre-infusion chamber

A small water-filled chamber inside an E61 (and similar) group that fills at line pressure before the pump kicks in, gently wetting the puck before full pressure.

Precision basket

A filter basket made with laser-drilled or electro-etched holes to tight tolerances (usually ±0.02mm), producing more uniform water flow across the puck.

Pressurised (dual wall) basket

A basket with a second wall and a single pin-hole exit that artificially generates pressure regardless of grind or technique, used on entry-level machines like Breville Bambino and the De'Longhi Dedica.

Removable brew group (ZBG)

A self-contained brewing unit — used in fully automatic bean-to-cup machines like Jura, Saeco, DeLonghi Magnifica and Miele — that can be slid out for cleaning and descaling.

Ridged vs ridgeless baskets

Most baskets have a pressed ridge near the top that engages with the portafilter's retaining spring. Ridgeless baskets (used with E61 portafilters fitted with a different spring) sit flush.

Saturated group

A brew group that is directly attached to (and shares water with) the brew boiler, keeping the group head at a stable, precise temperature at all times.

Semi-saturated group

A hybrid design where the group is heated by a dedicated element or circulating water from the brew boiler, offering better stability than a basic HX group but at lower cost than a fully saturated group.

Shower Screen

Perforated disc at the underside of the group that disperses water evenly across the puck during extraction.

Single basket / double basket / triple basket

Filter baskets sized for different doses — typically 7–10g (single), 14–22g (double), and 20–25g+ (triple).

Solenoid Valve

Electrically operated valve — a coil pulls a steel plunger to open a port, letting water, steam or air pass.

Spouted portafilter

A portafilter fitted with one or two spouts that split the espresso flow. Single-spout versions (single-dose) are for one cup, double-spout for two.

Acoustic/visual dosing cue

A beep or light signal that alerts the barista when a target weight or time is hit.

Brew chart (strength vs extraction)

A two-axis graph plotting TDS (strength) vs EY (extraction), with a "sweet spot" box defined by the SCA or the barista's own preference.

Extraction yield (EY %)

The percentage of the dry coffee mass that ends up dissolved in the cup. Measured by a refractometer.

Ideal extraction window

The EY range where the coffee tastes balanced — usually 18–22% for espresso and 18–23% for filter.

Over-extraction

A shot/brew where too much has been extracted, including bitter late-stage compounds. Typically tastes bitter, ashy, hollow, astringent.

Refractometer

An optical device that measures the refractive index of a liquid to calculate TDS. VST and Atago are the main brands.

Scale (timer scale)

A coffee scale with an integrated timer — most now Bluetooth-connected to apps.

TDS (total dissolved solids)

The percentage of the brewed liquid that is dissolved coffee (vs water). Measured by refractometer.

Under-extraction

A shot/brew where too little of the soluble material has been extracted. Typically tastes sour, thin, grassy, salty.

VST

The company founded by Vince Fedele that makes the industry-standard refractometer, laser-etched baskets, and ExtractMojo software.

Agitation

Any disturbance of the coffee grounds during brewing — swirling a V60, stirring a Clever, or the pump turbulence inside a puck.

Bloom (espresso)

The initial swelling and off-gassing of the puck during pre-infusion as CO₂ escapes from fresh coffee.

Boulders

Oversized particles (500+ microns) produced when burrs can't cut cleanly.

Brew ratio

The ratio of dose to yield — e.g., 18g in, 36g out is a 1:2 ratio.

Brew temperature

The actual water temperature meeting the coffee during extraction.

Channelling

Water finding a path of least resistance through the puck, bypassing most of the coffee and extracting intensely from a narrow zone.

Choker

A shot that runs far too slow or not at all — grind is too fine, or the puck is over-dosed.

Dose (weight in)

The mass of dry ground coffee loaded into the basket, measured in grams.

Dry puck

A firm, mostly-dry puck that knocks out as a solid cake.

Fines

Very small particles (under ~100 microns) produced as a byproduct of grinding.

Grind distribution

The spread of particle sizes in your grind — ideally, most particles are close to the target size (a "tight" distribution).

Grind size

The mean particle diameter of ground coffee, measured in microns (µm) — though most people just refer to "steps" on their grinder.

Gusher

A shot that runs far too fast — pouring in under 15 seconds at 1:2 ratio, usually from too-coarse grind or a severely channelled puck.

Levelling tool (distribution tool)

A spinner or paddle-style tool that rotates on top of the grounds to flatten the bed before tamping.

Nutation

Tilting the tamper slightly off-vertical during tamping, tracing a small cone to compress the basket edges.

Pre-infusion

Low-pressure phase at the start of a shot to wet the puck before full pressure.

Pre-infusion time

The duration of gentle puck saturation before full extraction pressure.

Puck preparation

The full sequence of steps between grinding and locking in — dosing, declumping/WDT, distributing, levelling, tamping.

Puck screen

A thin metal mesh disc (usually 58mm, 0.2–1.7mm thick) placed on top of the tamped puck.

Shot time (extraction time)

The elapsed time from when the pump starts to when you stop the flow at the target yield.

Soupy puck

A wet, sloppy puck that falls out of the basket in chunks rather than a firm disc.

Spritzing

Visible fine droplets shooting sideways out of a bottomless portafilter during extraction — a symptom of channelling.

Tamp pressure

The force applied to the tamper when compressing the puck. Historically cited as ~30lb, but now understood to matter much less than uniformity.

Tamper fit (58mm, 58.35mm, convex vs flat)

The diameter and shape of the tamper base relative to the basket inner diameter.

Tamping

Compressing the grounds in the basket with a tamper, producing a flat, uniformly dense puck.

Unimodal vs bimodal distribution

Unimodal distribution has one peak (most particles at one size). Bimodal has two peaks (lots of fines AND lots of target-size particles).

WDT (Weiss Distribution Technique)

Using a thin tool (needle, acupuncture needle) to stir the grounds in the basket before tamping, breaking up clumps and redistributing density.

Yield (weight out)

The mass of liquid espresso produced by the shot, measured in grams (not millilitres).

Anti-static plate / RDT

A grounded metal plate inside the grinder chute (anti-static), or the technique of spritzing the beans with 1–2 drops of water (Ross Droplet Technique) to reduce static charge.

Bellows

A rubber or silicone bulb that fits over the hopper opening of a single-dose grinder, used to purge residual grounds from the burr chamber.

Chute

The channel or tube that guides ground coffee from the burrs out to the portafilter.

Declumper

A wire mesh or perforated screen in the grinder chute that breaks up clumps of ground coffee before they hit the basket.

Doser

Chamber with a paddle that delivers a measured dose into the portafilter.

Doserless (on-demand)

A grinder that grinds directly into the portafilter on demand, with no intermediate dosing chamber. Usually triggered by a button or a portafilter sensor.

Dosing cup

A small metal cup (often 58mm OD) used to catch grounds from the grinder, then invert into the basket.

Dosing funnel

A magnetic ring or funnel that sits on top of the basket to guide grounds in without spilling, often used with single-dose workflows.

Grind by eye

The old-school method of eyeballing the amount of ground coffee in the basket.

Grind by time

An on-demand grinder that runs the motor for a programmed duration (e.g., 6.2 seconds) to deliver a dose.

Grind by weight

An on-demand grinder with an integrated scale under the portafilter cradle, stopping the motor when the target weight is reached.

Hopper grinding

Loading a large quantity of beans into a hopper and dosing shots on-demand.

Primed on-demand

An on-demand grinder that always holds a small amount of coffee in its grind path, dispensing whatever was ground previously and replacing it with a fresh batch.

Purge (grinder)

Running a small amount of coffee through the grinder to clear residual grounds before dosing fresh beans.

Retention

The amount of ground coffee trapped inside the grinder path after a grind cycle.

Single dosing

Weighing out exactly one shot's worth of beans (e.g., 18g) and loading them into the grinder for each shot — no hopper.

Stepless (micrometric) adjustment

A grind adjustment that varies continuously with no fixed increments.

Stepped adjustment

A grind adjustment system with fixed increments (clicks) — e.g., 40 steps between espresso and filter.

Worm gear adjustment

A fine, high-resolution grind adjustment mechanism using a worm-and-gear drive — used on precision grinders like the Weber Key.

Burr

The cutting elements inside a grinder — flat or conical, steel or ceramic — that shear coffee beans into a controlled particle size.

Burr alignment

Making sure the two burrs are perfectly parallel to each other.

Burr chirp

The sound the burrs make when they touch each other with no coffee in between — used to find the zero point.

Burr diameter

The cutting-surface diameter of the burrs — common sizes are 50mm, 58mm, 64mm, 75mm, 83mm, 98mm.

Burr material

The metal or ceramic the burrs are made from — hardened steel, titanium-coated steel, red-speed steel (HSS), or ceramic.

Burr seasoning

The process of running 5–20kg of coffee through new burrs to smooth micro-roughness on the cutting edges.

Conical burr

A cone-shaped inner burr and a matching hollow outer ring, grinding beans as they pass between the tapered surfaces.

Direct drive vs belt drive

The burr carrier is either attached directly to the motor shaft (direct drive) or connected via a belt (belt drive).

Flat burr

Two horizontally mounted, parallel-faced burrs that grind coffee between their flat cutting surfaces as beans enter from the centre.

Hopper

Bean container mounted on top of the grinder.

Hybrid (ghost) burrs

A newer burr geometry (pioneered by SSP and Lagom) that combines aspects of both flat and conical designs, often marketed as producing "high clarity" or "sweet" cups.

Motor type (DC vs AC)

Grinder motors are either direct current (DC, usually with a control board) or alternating current (AC, simpler, usually 1400 rpm).

RPM (grinder speed)

Revolutions per minute of the burrs. Commercial AC motors run at 1400 rpm; high-end DC motors run at 400–900 rpm.

Zero point

The grind setting at which the burrs just barely touch (make contact without coffee).

10-year service

A major overhaul for prosumer machines — replacing gaskets, seals, flow restrictors, shower screens, pump parts, pressurestat and thermostats.

Backflush (clean)

Locking a blind basket into the group and running a short brew cycle with espresso machine cleaner, forcing cleaning solution backwards through the three-way valve to flush oils and residue.

Backflush (water only)

Backflushing with plain water, with no detergent.

Blind disc / blind basket / blanking disc

A solid rubber (or metal) disc that fits into the portafilter to block flow, used for backflushing or OPV adjustment.

Boiler scale

Calcium carbonate deposits left behind by evaporated water, coating boiler interiors and restricting flow.

Descaling agent

A mild acid (citric, lactic, or phosphoric) used to dissolve limescale from boilers and water paths.

Dispersion screw

The single screw holding the shower screen (and sometimes dispersion block) onto the group.

Gasket replacement

Replacing the rubber portafilter gasket — a 10-minute job on most machines.

Gicleur sizing

Changing the jet inside an E61 group to alter pre-infusion aggressiveness.

Grinder burr replacement

Fitting new burrs to your grinder — typically every 500–1000kg of coffee for steel burrs.

Grinder cleaning tablets (Urnex Grindz, Cafiza)

Rice-shaped or granular cleaning media that runs through a grinder to absorb oils and flush out fines.

Group cleaner (Cafiza, Puly Caff)

An alkaline detergent powder or tablets designed to dissolve coffee oils.

O-Rings & Seals

Round rubber seals used throughout the machine — group, valves, taps, fittings. Cheap to stock, instant fix for nine in ten leaks.

OPV adjustment

Tweaking the over-pressure valve spring preload to change the maximum pump pressure.

Pump rebuild

Replacing the internal pistons, o-rings or bypass springs on a pump. Standard for rotary pumps after 5–10 years; vibe pumps are usually replaced as a unit.

Service interval

The recommended frequency for machine and grinder servicing — usually every 12 months for home use, every 3–6 months for cafés.

Shower screen replacement

Removing and swapping the shower screen, usually held by a single centre screw.

Steam wand purge

Running steam through the wand briefly after each steaming session to clear residual milk from the tip.

Barista milk

A milk formulation (dairy or plant) designed specifically for steaming and textures — usually higher protein and sometimes added stabilisers.

Etching

Using a tool (latte art pen, skewer) to draw patterns in the foam surface.

Free pour

Pouring latte art without etching or toppings — using jug movement alone to create patterns.

Heart / tulip / rosetta / swan / wave (stacked tulip)

Common latte art patterns, listed roughly in order of difficulty.

Latte art jug (milk pitcher)

The stainless steel jug used to steam and pour milk. Common sizes: 350ml (for 1 drink), 600ml (for 2), 900ml+ (commercial).

Microfoam

Milk foam where the bubbles are so small they can't be seen individually — appearing as a glossy, paint-like surface.

Milk fat content

The percentage of fat in milk — full cream (~3.5%), light (~1.5%), skim (<0.5%).

Plant milk performance

How well different plant milks behave under steam.

Split jug technique

Pouring from one jug into two cups simultaneously, saving time in busy cafés.

Spout type (standard, sharp/tulip)

Different spout profiles — wide standard spouts for big pours, sharp/tulip spouts for precision latte art.

Steaming

Injecting steam into milk to heat it.

Stretching

The first phase of steaming, where the wand tip is held near the milk's surface to draw air in, creating foam.

Texturing

The second phase of steaming, where the wand is buried deeper and the milk is vortexed to break up big bubbles into silky microfoam.

9 bar standard

The industry-standard espresso extraction pressure — 9 bars (about 130 psi, or 9 times atmospheric pressure).

Boiler pressure gauge

The manometer that displays steam boiler pressure (0–2.5 bar typical range).

Brew pressure gauge

A manometer that reads the actual pressure at the group during a shot.

Capacitor

Energy-storage component used to start vibration pumps and run motors — fails closed or fails open and your machine won't pump.

Flow profiling

Controlling water flow rate (rather than pressure) during a shot. Pressure becomes a consequence of the flow you dictate and the puck's resistance.

Gear pump

A continuous-flow positive-displacement pump using meshing gears. Common in larger commercial espresso machines and brewers where smooth, quiet, low-pulsation flow is needed.

Line pressure pre-infusion

Using municipal or reservoir water pressure (0.5–3 bar) to gently wet the puck before the main pump kicks in at 9 bar.

Pressure Gauge

Analog dial showing pump (brew) pressure or boiler (steam) pressure — your primary diagnostic instrument.

Pressure profiling

Varying the pressure applied to the puck during the extraction — e.g., starting at 2 bar for 10 seconds, ramping to 9 bar, then declining to 6 bar at the end.

Pressure ramp

The speed at which pump pressure rises from zero to full during the start of an extraction.

Pulse pre-infusion

A technique where the pump is switched on and off in bursts at the start of the shot, using the machine's existing plumbing to simulate soft pre-infusion.

Pump expansion valve

A small one-way valve that releases excess pressure created by water expanding as the boiler heats up. Without it, cold-fill water would push past the pump and damage seals.

Pump Head / Brass Pump

The brass body of a rotary pump — contains the rotor, vanes, and bypass valve that build brew pressure on plumbed-in machines.

Pump Motor

AC induction motor that drives a rotary pump head — runs continuously while the pump is engaged.

Pump pressure vs brew pressure

Pump pressure is what the pump outputs (limited by the OPV); brew pressure is what the puck actually sees, which can be lower due to flow restriction and gicleur effects.

Rotary Pump

Quiet, continuous-pressure pump driven by a separate motor — standard on commercial machines and high-end prosumers.

Vibration Pump

Compact, inexpensive electromagnetic pump that pulses water at 50 Hz — standard on home and entry-level machines.

Articulating wand (ball-joint wand)

A steam wand with a multi-directional joint, letting you position the tip at any angle and height.

Auto-purge

A feature on some machines (notably La Marzocco Linea Mini, Rocket R Nine One, higher-end Breville) that automatically purges the steam wand after you finish steaming.

Cool-touch wand (no-burn wand)

A double-walled or insulated steam wand that stays cool to the touch.

Hot water tap

A dedicated outlet (usually operated by a tap or button) that dispenses hot water from the steam boiler for Americanos, teas, or pre-heating cups.

Mixer tap

A hot water outlet that blends boiler water with fresh cold water on the way out, giving cooler, better-tasting water than raw boiler water.

Steam tip

The removable nozzle at the end of the steam wand with 1–6 holes drilled at specific diameters and angles.

Steam Wand

Articulating tube that delivers dry steam for milk texturing.

Tap / Steam Valve Assembly

The whole knob, stem, seal and seat assembly behind a steam or hot-water tap — drips and stiff knobs come from worn seats and o-rings inside.

Wand & Tip

The pipe and removable tip nozzle that delivers steam to the milk jug — tip hole count and size define how the wand handles different volumes.

BWT

Best Water Technology — an Austrian water filter manufacturer widely used in specialty cafés for their magnesium-dosing filters.

GH (general hardness)

Total mineral hardness of water, measured in parts per million or German degrees (°dH).

KH (carbonate / temporary hardness)

The portion of hardness made up of bicarbonates (the scale-forming component).

Pentair / Everpure

Major American water filtration manufacturer (Pentair owns Everpure), popular for commercial food service filtration.

pH

Acidity/alkalinity, 0–14 scale, 7 is neutral.

Remineralisation

Adding minerals back to water that has been too heavily filtered (e.g., RO water).

Reverse osmosis (RO)

A filtration method that forces water through a semi-permeable membrane, removing up to 99% of dissolved solids.

SCA water standards

The Specialty Coffee Association's guidelines for ideal brewing water — target 150 ppm TDS, ~50–80 mg/L calcium carbonate hardness, pH 6.5–7.5.

TDS (water)

Total dissolved solids in water, measured in parts per million.

WaterMark certification

The Australian mandatory certification for plumbing products that come into contact with drinking water.

Autofill probe

A stainless probe inside the steam boiler that detects the water level by electrical conductivity, telling the autofill solenoid when to refill.

Check Valve

A one-way valve that lets water flow in only one direction. Found on the pump outlet, autofill line and group inlet to stop hot/pressurised water from flowing back where it shouldn't.

Drip tray

The removable basin under the group and steam wand that catches drips, purges and rinse water — usually with a grate on top and either a drain hose out the back or a full-tray indicator.

Expansion Valve

Adjustable safety valve that bleeds excess pressure from the boiler back to the inlet, protecting plumbing from thermal expansion.

Float valve

A mechanical valve held shut by a buoyant float. As water drops, the float falls and opens the valve; water rises, the float lifts and shuts it. Common on lever machines and simple boilers.

Flowmeter

Small turbine sensor that counts water passing through it in pulses — used by volumetric machines to dose shots by volume rather than time.

Grate

The slotted top plate on the drip tray that supports cups under the group. Usually stainless steel; on some commercial machines it can be perforated, slatted, or rubber-coated.

Level sensor

Generic term for any device that measures water level — covers conductive autofill probes, capacitive sensors, optical sensors and float-based switches.

Plumb-in

Connecting an espresso machine directly to mains water (with appropriate filtration and pressure regulation) instead of using the internal reservoir.

Reservoir (tank)

The removable cold-water tank on a non-plumbed espresso machine. Feeds the pump on demand and includes a low-water sensor so the machine stops before running dry.

Sight glass

A clear (usually borosilicate) tube on the side of a steam boiler that shows the current water level at a glance — common on traditional commercial machines.

Tubing & Hose (PTFE / Silicone / Braided)

Internal water and steam lines — PTFE for high-temperature brew water, silicone for low-pressure cold lines, braided stainless for plumbed inlets.