Home › Espresso Machines › Pressurised vs non-pressurised baskets
🔧 Accessories · 2026A dual-wall basket regulates pressure for you and makes crema mechanically; a single-wall basket lets grind, dose and tamp decide the shot. How to tell which you have, and which you want.
Written and reviewed by the CoffeeLabAdvisor editorial team · Published 9 September 2026
Look at the underside of your basket. Many small holes across the whole floor means single wall, also called non-pressurised: the coffee bed is the only resistance, so grind, dose and tamp all change the shot. One small hole under an inner floor means dual wall, also called pressurised: Breville's own manual says these baskets “regulate the pressure and help to optimize the extraction regardless of the grind, dose, tamp pressure or freshness”. Breville's rule for choosing is simple — single wall “if grinding fresh whole coffee beans”, dual wall “if using pre-ground coffee”.
Cutaway of both. The single wall lets the coffee bed set the resistance; the dual wall sets it with a restriction of its own, which is why grind matters much less in one than the other.
Lift the basket out of the portafilter and turn it over.
Dozens of small holes spread across the whole floor — a single wall, non-pressurised basket. Water leaves through the coffee across the entire base, so the only thing slowing it down is the coffee itself.
One small hole, or a few, in the middle of an otherwise solid-looking floor — a dual wall, pressurised basket. There is a second floor inside with the real filter holes, and a chamber between the two. Water has to build up before it can leave through that single outlet.
If your machine came with two sets of baskets and you have never noticed, that is normal and worth fixing: Breville ships both, listing “Dual Wall filter baskets (1 cup & 2 cup)” and “Single Wall filter baskets (1 cup & 2 cup)” as separate accessories, each labelled for a different job.
Many entry-level machines ship with only the pressurised type and do not advertise the fact, which is one of the reasons a cheap machine can feel like it produces good espresso immediately and then resist every attempt to improve.
Breville's instruction book explains both in a single pair of sentences, and it is worth reading them as a statement about control rather than quality.
On single wall: “Use Single Wall filter baskets if grinding fresh whole coffee beans. Single Wall filter baskets allow you to experiment with grind, dose and tamp to create a more balanced espresso.”
On dual wall: “Use Dual Wall filter baskets if using pre-ground coffee. Dual Wall filter baskets regulate the pressure and help to optimize the extraction regardless of the grind, dose, tamp pressure or freshness.”
Read that last clause again, because it is the whole thing: regardless of the grind, dose, tamp pressure or freshness. A pressurised basket is a machine that makes your four biggest variables stop mattering. Whether that is a feature or a limitation depends entirely on whether you wanted them to matter.
| Single wall (non-pressurised) | Dual wall (pressurised) | |
|---|---|---|
| Sets the resistance | The coffee bed | The basket's own restriction |
| Grind matters | Enormously | Very little |
| Tamp matters | Yes | Very little |
| Stale coffee | Shows immediately | Largely hidden |
| Crema | From extraction — a sign of the shot | Made mechanically — not a sign of anything |
| Ceiling | As good as your technique and grinder | Reliably fine, and no better |
Crema on a properly extracted espresso is a by-product of dissolved carbon dioxide from fresh coffee coming out of solution under pressure. It is loosely informative: thin, pale crema on fresh coffee usually means something went wrong.
On a pressurised basket, crema is produced mechanically. Coffee forced through one small outlet at speed aerates, and that produces a foam whether the extraction underneath was good, bad or indifferent. It will appear on stale supermarket pre-ground with a careless tamp, because the basket generates it by design.
Two practical consequences. First, you cannot use crema to judge a shot from a pressurised basket — the most common visual feedback loop in espresso is switched off. Second, the crema tends to look impressive and dissipate quickly, and it carries a slightly different, lighter texture than extraction crema. Our crema page covers what it is and what it does and does not tell you.
None of this makes the coffee bad. It makes the coffee uninformative, which matters only if you were planning to learn from it.
Stay with pressurised if: you buy pre-ground coffee and intend to keep doing so, you have no grinder and no plans to buy one, or you want a reliable milk-drink base with no dialling in. There is nothing embarrassing about this. A pressurised basket delivers a consistent, decent result from ingredients that would otherwise produce a bad one, which is exactly what it was designed for.
Switch to single wall if: you grind fresh, or you are about to. This is the upgrade order that matters — a single-wall basket without a decent grinder makes espresso worse, because now the grind is the resistance and pre-ground coffee is the wrong grind. Get the grinder first, then the basket. Our espresso grinder guide covers what is required, and our grinding guide covers doing it.
When you do switch, expect to re-learn the machine. Breville warns about the smaller version of this: “You will need to adjust the grind amount and size if switching from a single basket to a double basket, or vice versa.” Moving from dual wall to single wall is a bigger change again — the first few shots will run fast and taste sour, and the answer is a finer grind.
Dose figures help here, because a single-wall basket is unforgiving about them. Breville states its supplied baskets are designed for “1 CUP basket = approx. 8-11g” and “2 CUP basket = approx. 16-19g”. Our tamper guide covers getting the bed level once the dose is right.
This is harder to answer than it should be, because makers are inconsistent about publishing it — and where a maker does not state it, we do not either.
Breville is the clearest: the Dual Boiler listing names “1 Cup & 2 Cup Single and Dual Wall Filter Baskets” among the supplied accessories, and the Barista Express manual lists both sets with the instruction for each. If you own a Breville, you very likely already have the single-wall baskets in the box.
De'Longhi does not settle it for the machines we have documented. Both our Stilosa and Dedica profiles record the same gap: De'Longhi's materials state that two filters are supplied for single and double espresso, but not whether those filters are pressurised. Those pages tell you to ask before buying, and this page is why that question matters rather than being pedantic — at that price it is the difference between a machine you can develop with and one you cannot.
If you are shopping and it matters to you, the questions to ask a seller are: are the supplied baskets pressurised, and are non-pressurised baskets available for this model. The second is the more important one, because a machine with a common basket size can be upgraded later. Our portafilter size chart lists the sizes, and 58 mm and 54 mm both have wide aftermarket support.
Bottomless portafilters, which are always non-pressurised and show you the extraction directly, plus the tools that matter once the basket stops hiding your mistakes.
Listing states compatibility with Rancilio Silvia Pro, Silvia Pro X and all other Rancilio home models, plus commercial Silvia, Epoca and Classe
Check price on Amazon →
Listing states compatibility with Breville Barista Express, BES880BSS, BES870XL, BES878BSS, BES500BSS, BES840XL, Pro, Touch, Bambino Plus, Infuser and Duo Temp Pro
Check price on Amazon →
Listing states a calibrated spring-loaded tamper with a 53.3 mm base described as a better fit for 54 mm Breville portafilters than common 53 mm tampers, naming the Barista Express, Barista Pro, Barista Touch, Bambino Plus, Infuser and Duo Temp Pro
Check price on Amazon →
Listing states 0.3 mm spring wires, 9 prongs, anodized aluminium handle - needle diameter, not basket size, is the fit that matters for a WDT tool
Check price on Amazon →Turn it over. Many small holes across the whole floor means single wall, non-pressurised. One small hole in an otherwise solid-looking floor means dual wall, pressurised — there is a second floor inside with the real filter holes and a chamber between them.
What sets the resistance. In a single wall basket the coffee bed does, so grind, dose and tamp all change the shot. In a dual wall basket the basket's own restriction does — Breville's manual says dual wall baskets regulate the pressure and help optimise extraction regardless of the grind, dose, tamp pressure or freshness.
Breville's own rule: single wall if you are grinding fresh whole beans, dual wall if you are using pre-ground coffee. The order matters — a single wall basket without a decent grinder makes espresso worse, not better, because the grind becomes the resistance and pre-ground is the wrong grind.
It is real foam, but it does not indicate a good extraction. A pressurised basket makes crema mechanically by forcing coffee through one small outlet, so it appears whether the extraction was good or not. That means you cannot judge a shot by its crema on a pressurised basket.
Only if you grind fresh. It removes the basket's help, which improves the ceiling and lowers the floor. With a burr grinder you can adjust, it is a genuine upgrade; with pre-ground coffee it will make things worse.
De'Longhi does not state it in any materials we could verify, so we do not claim either way. Both machines are documented as supplying two filters for single and double espresso, with the basket type unstated. If it matters to your buying decision, ask the seller directly — and also ask whether non-pressurised baskets are available for the model.
Breville states its supplied baskets are designed for approximately 8 to 11 g in the 1-cup basket and approximately 16 to 19 g in the 2-cup basket. A single wall basket is far less forgiving about dose than a pressurised one, so weighing it is worth the trouble.
Sources for this page: The single-wall and dual-wall instructions quoted in full, the statement that dual wall baskets regulate the pressure regardless of grind, dose, tamp pressure or freshness, the accessory list naming both basket sets, the 1-cup and 2-cup dose figures of approximately 8-11 g and 16-19 g, and the warning that grind must be adjusted when switching baskets: Breville's own instruction book for the Barista Express (BES870), read 2026-09-09 · The Dual Boiler's supplied single and dual wall filter baskets: Breville's own copy on the verified Amazon listing B00I6JGGP0 via the Creators API, read 2026-09-09, and Breville's product page for the Dual Boiler · That De'Longhi does not state whether the Stilosa's or Dedica's supplied baskets are pressurised: recorded as an unstated specification on our own profiles of both machines, from De'Longhi's materials read 2026-09-08 and 2026-09-09 · Crema formation and what it does and does not indicate: our own crema page and the sources cited there · Bottomless portafilter and tool specifications: the makers' own copy on the verified Amazon listings in our accessories catalog 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.