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📋 Reference · 2026The parts of an espresso machine in the maker's own names, and the specific failure each one produces when it needs attention.
Written and reviewed by the CoffeeLabAdvisor editorial team · Published 9 October 2026
A home espresso machine has about a dozen named parts, and the useful way to learn them is in the order the water meets them: water tank → pump → thermocoil → group head → shower screen → portafilter → filter basket → cup, with the steam wand, drip tray and cup warming tray hanging off that path. The names below are taken from Breville's own labelled component list rather than invented, and each one is paired with the symptom it produces when it is the part at fault.
The parts a home espresso machine is actually made of, in the order the water meets them. Every name here is the manufacturer's own.
Rather than paraphrase, here is how Breville labels the components of one of its espresso machines, verbatim from the instruction book's KNOW YOUR BREVILLE PRODUCT
page:
Thermocoil heating system accurately controls water temperature.
Integrated removable tamper for tamping control.
Group head for easy positioning of the portafilter.
54mm stainless steel portafilter with commercial style spouts.
Drip tray full indicatorand
Removable drip tray
Cup warming tray
Control dial for espresso, steam and hot water.
Swivel steam wand easily adjusts to perfect position for texturing milk.
Two more are listed as not shown on the diagram: a Removable 1.8L water tank filled from the top with integrated water filtration
, and a Storage tray located behind the drip tray for storage of accessories.
That is the whole machine. Everything else you will read about — solenoids, OPVs, pressure gauges — is either internal, or specific to machines above this class.
The group head is the fitting the portafilter twists into, and where water enters the coffee. Inside it sits the shower screen, which spreads the stream across the whole puck instead of drilling a hole through the middle of it.
The component that fails here is neither of those. It is the rubber ring around the screen, and Breville names the symptom precisely: The silicone seal surrounding the shower screen needs to be replaced to ensure the portafilter is properly secured into the group head.
So a machine that has started leaking around the handle, or whose portafilter no longer feels like it tightens, is usually telling you about a perished seal rather than a dying pump. It is a cheap part and a common one.
The portafilter is the handled device that holds the coffee. Its diameter is the single most important number about your machine for buying accessories — 54 mm on Breville's smaller range, 58 mm on most prosumer machines.
The basket drops into it, and which one you use is not a matter of size. Breville's instruction is explicit: If using whole bean coffee ground directly before extracting, use the Single Wall Filter Baskets. If using Pre-ground coffee, use the Dual Wall Filter Baskets.
That matters more than it sounds. A Dual Wall basket regulates pressure for you, which is forgiving — and also the reason your grind adjustments can seem to do nothing at all. If you are trying to dial a shot in and the machine will not respond, check which basket is fitted before you change anything else.
Most home machines heat water with a thermocoil: water passes through a heated coil on its way to the group, rather than sitting in a boiler waiting. It is why these machines are ready in seconds rather than minutes.
It also explains a behaviour that worries new owners. Breville lists it under troubleshooting, as normal: Auto purge feature. Immediately after the espresso, hot water and steam functions, the machine will purge water into the drip tray. This ensures the thermocoil is at the optimal temperature.
So a drip tray that fills faster than your drips can account for is the machine dumping the over-hot water left after steaming, so the next shot is not brewed at steam temperature. Nothing is broken. The manual's own advice is simply to empty the tray when the indicator shows.
The pump pressurises water to force it through the puck. Home machines are near-universally specified at 15 bar, though the pressure actually reaching the coffee during a shot is lower and should be.
The pump is also the loudest part of the machine, and the noise is listed as expected behaviour rather than a fault: a pulsing or pumping sound while extracting or steaming is, in Breville's words, the normal operation of the 15 bar Italian pump
, with No action required as this is the normal operation of the machine.
One genuine fault does sit nearby. If the machine switches itself off mid-use, the manual points at The safety thermal-cutout may have activated due to the pump or grinder overheating.
— the remedy being to unplug it and let it cool for thirty to sixty minutes rather than keep trying.
The steam wand injects steam into milk to heat and texture it in one motion. On most machines it swivels, which matters more than it sounds: the angle sets whether the milk spins into a vortex or just boils.
The drip tray catches drips, purge water and whatever misses the cup. It lifts out, and the manual asks for it to be removed, emptied and cleaned at regular intervals
with warm soapy water and a non-abrasive liquid. Behind it, on many machines, is a storage tray for the accessories.
The cup warming tray on top is not decoration. A cold cup pulls several degrees out of a 30 ml drink immediately, which is a meaningful fraction of the temperature you spent money controlling.
Worth separating, because the two get confused when people order replacements. Breville lists its supplied accessories separately from the machine's components: a Razor™ Precision Dose Trimming Tool
, Single wall filter baskets for freshly ground coffee
, Advanced dual wall filter baskets for pre-ground coffee
, a water filter, a stainless steel milk jug, and under cleaning accessories a cleaning tool and a silicone cleaning disc.
The cleaning tool is the one people throw away and later need: it carries a pin for clearing blocked basket holes. The manual's fuller remedy for a basket that will not clear is to dissolve a cleaning tablet in hot water and soak filter basket and portafilter in solution for approx. 20 minutes
.
The silicone disc is the blanking disc used for backflushing on machines that support it. If yours came with one and you have never used it, that is the part to read up on next.
The consumables that keep the parts on this page working. A water filter protects the thermocoil, cleaning tablets clear the shower screen and basket, and a dosing funnel stops grounds landing on the group head seal.
The two-month filter the manuals credit with reducing how often you descale; six is a year. Listing states the filters fit the Barista Pro BES878, Barista Express BES870, Infuser BES840 and Duo-Temp Pro BES810, plus earlier batches of the Oracle, Oracle Touch and Dual Boiler, with a recommended change every 2 months.
Check price on Amazon →
For the other job on an espresso machine - the backflush - not for descaling. Listing states professional espresso machine cleaning tablets that remove coffee residue and oils from group heads, valves and lines, recommended as part of a daily backflush regimen, OMRI listed and NSF certified.
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The answer to the size question: 53.3 mm, which is what a 54 mm-class portafilter actually takes. Listing states a 0.2 mm thick 316 stainless steel puck screen measuring 53.3 mm, supplied in a 3-pack, and lists compatibility with the Ninja ES601 and Ninja Luxe Café as well as the Breville Barista Express, Barista Express Impress, Barista Touch, Bambino and Bambino Plus, and most 54 mm portafilter machines. It notes it is not recommended where the shower head has protruding screws.
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Keeps the grounds in the basket while you WDT - the cheapest tidy-up on the bar. Listing states an 18 mm anodized aluminium dosing ring for 58 mm portafilters held by nine pressed-in neodymium magnets, with knurled edges for lifting, for grinding into the basket and using a WDT tool without spills.
Check price on Amazon →The fitting the portafilter locks into, where water enters the coffee. Inside it is the shower screen, which spreads water across the puck; the silicone seal around that screen is the part that commonly fails, and Breville names the symptom as the portafilter no longer being <q>properly secured into the group head</q>.
Breville's instruction is <q>If using whole bean coffee ground directly before extracting, use the Single Wall Filter Baskets. If using Pre-ground coffee, use the Dual Wall Filter Baskets.</q> A Dual Wall basket regulates pressure for you, which is also why grind changes can seem to have no effect in one.
It is the auto purge. Breville describes it as normal: immediately after espresso, hot water and steam, <q>the machine will purge water into the drip tray. This ensures the thermocoil is at the optimal temperature.</q>
Yes. The manual attributes it to <q>the normal operation of the 15 bar Italian pump</q> during extraction and steaming, and says no action is required.
Measure the basket's outer diameter. Breville's smaller machines use a 54 mm portafilter — the manual calls it a <q>54mm stainless steel portafilter with commercial style spouts</q> — while most prosumer machines use 58 mm.
A heating system that warms water as it passes through a coil, rather than holding a reservoir of hot water. Breville describes it as a <q>Thermocoil heating system accurately controls water temperature.</q> It is why these machines reach brewing temperature in seconds.
Sources for this page: The labelled component list (thermocoil heating system, integrated removable tamper, group head, 54mm stainless steel portafilter, drip tray full indicator, removable drip tray, cup warming tray, control dial, swivel steam wand, the 1.8 L removable water tank and the storage tray), the supplied accessories list including the Razor Precision Dose Trimming Tool and the silicone cleaning disc, the Single Wall and Dual Wall basket instruction, the 20-minute cleaning-tablet soak and the drip tray cleaning instruction: Breville Duo-Temp Pro BES810 instruction book (BES810BSS_USC_IB_C14), “KNOW YOUR BREVILLE PRODUCT” and cleaning sections, read from the PDF on 2026-10-09 · The shower screen silicone seal symptom, the auto purge explanation, the 15 bar Italian pump noise note and the safety thermal-cutout entry: Breville Barista Express BES870 instruction book, troubleshooting section, read from the PDF on 2026-10-09 · Accessory specifications on the cards below: each product's own Amazon listing copy, read 2026-10-09 We have not lab-tested brewers; where a figure is a manufacturer's, the page names the manufacturer, and machine capabilities come from our own published review records.