Espresso Baskets: Single Wall, Dual Wall, VST and IMS
If you grind fresh, use a single wall basket. Dual wall baskets, often called pressurized, are for pre-ground coffee and regulate the pressure for you, so they hide the grind changes you're trying to learn from. Precision baskets from VST and IMS are a later step, and the ones we read about fit 58 mm portafilters.
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Single wall baskets have one layer of holes, so grind, dose and tamp decide how the shot runs. Dual wall, or pressurized, baskets regulate the pressure, and Breville recommends them for pre-ground coffee. Use single wall if you grind fresh and weigh your shots. Before you buy a precision basket such as VST or IMS, check your portafilter size, because the ones we read about are 58 mm.
On this page
A basket looks like the least interesting part of the machine, and it decides more about your morning than the number on the box. If you weigh your shots, the choice of wall type comes first: one type shows you what your grind is doing, and the other was built to smooth that over.
We compare by manuals and maker pages, and we run no flow or taste trials of our own.
Which basket for which setup
If you grind fresh and want to dial in
If you buy pre-ground coffee
If you want a machine that ships with both wall types → Breville Bambino
View(paid link to Amazon, opens in a new tab)Ad · paid link · check price & delivery on AmazonIf you want to look at a budget machine's baskets first
Single wall vs dual wall
| Single wall (non-pressurized) | Dual wall (pressurized) | |
|---|---|---|
| Breville recommends it for | Fresh whole beans you grind yourself | Pre-ground coffee |
| What sets the flow | Your grind, dose and tamp | The basket regulates the pressure |
| What it shows you | Grind changes show up in shot time and taste | Much less, by design |
| Who should use it | Anyone with an espresso-capable grinder | Anyone without one |
Breville's manual says dual wall baskets help the extraction regardless of grind, dose, tamp pressure or freshness. For a beginner on pre-ground, that's a real help. If you're trying to learn, it's the reason to switch: your scale and timer can't teach you much when the basket is correcting for you.
What a single wall basket asks of you
Without a second wall to regulate the flow, the coffee bed does the work. Clumps and uneven spots matter more, which is why puck prep belongs with this choice. A bottomless portafilter lets you see how a single wall shot runs.
What ships with which machine
Check the box first, because you may already own the right basket.
| Machine | Baskets in the box | Source |
|---|---|---|
| Barista Express, Impress | Single and dual wall, 1 and 2 cup, 54 mm | Breville pages |
| Bambino | Single and dual wall, 1 and 2 cup; a 2 cup single wall comes installed | Manual |
| Bambino Plus | Single and dual wall on the product page; the 2020 manual lists dual wall | Breville, so check your box |
| Gaggia Classic Evo | “Crema perfetta” 1 or 2 cup, plus traditional 1 and 2 cup | Gaggia manual |
| Smeg EMC02 | Pressurized and non-pressurized filters, plus a blind filter | Smeg US page |
| De'Longhi Stilosa | Single and double filters; wall type not stated | De'Longhi page |
| Ninja Luxe Café, ES601ANZ | Single, double and luxe; the machine detects which one is in | Ninja guide |
Gaggia's manual says the “Crema perfetta” filter only goes with the frothing jet device, and that the traditional filters are the ones like those in professional bar machines, which take more skill. The filter you start on is a choice worth making on purpose.
Budget machines often come with less documentation. Our CASABREWS page goes through what we could find on the CM5418* and its siblings.
The basket sits right above this. Its holes are the last thing your coffee passes through.
Precision baskets: what VST and IMS publish
These are single wall baskets sold on how carefully the holes are made. What we can report is what the makers and sellers publish.
| VST 18 g | IMS B702TH24.5M | |
|---|---|---|
| Who says | iDrinkCoffee, a retailer | IMS |
| Dose | Designed for 16 to 19 g | 16/18 g dark roast, 17/19 g medium, 20/22.5 g light |
| Holes | Each measured to ±30 microns | 641 holes, 0.30 mm |
| Fit | Standard 58 mm portafilters | Tamper Ø 58/58.4 mm |
| Ridge | Standard has one; a ridgeless version is listed | Height 24.5 mm; ridge not stated on the page |
Neither number tells you what a shot will taste like, and we found no independent comparison that we could read and vouch for. If your grinder, dose and tamp already repeat well, a precision basket may be a sensible next thing to try. If they don't, it won't fix them.
Those two aren't on Amazon in our data. These two ridgeless 58 mm baskets are, and we only have their listings, so neither is a pick:
Velvet Flow* is listed for 18 to 21 g, and μ* as a low-dose basket with no gram range in the title. Both titles name 58 mm portafilters, so they won't suit a 54 mm Breville.
How to match a basket to your dose
- Size first. Baskets for 51, 54 and 58 mm don't swap. A Gaggia Classic is 58 mm per Gaggia, and Breville's Express and Bambino lines are 54 mm per Breville. Portafilter sizes has more.
- Then the rated dose. Breville's 54 mm machines list 18 g as the ideal. If you want to dose higher, you need a basket rated for it. Espresso dose covers how to choose.
- Then the tamper. A new basket can change the fit. Our tamper guide explains how to measure.
- Change one thing at a time. A new basket can shift your flow, so re-dial it, and don't change the grinder the same week.
Still choosing the machine these baskets go in? These questions end in one model, and the start page begins with what you drink:
Our recommendation
Use what's in your box. Move to the single wall basket as soon as you grind fresh, and stay there. Buy a precision basket only when your routine already repeats, and only in a size that fits. We compare by listing, maker pages and published sources, and how we compare explains what “Seller data only” means on the cards above.
Asked at the bar
What is the difference between a pressurized and a non-pressurized basket?
A pressurized basket, which Breville calls dual wall, regulates the pressure and helps the shot along whatever your grind, dose, tamp or bean freshness. A non-pressurized basket, or single wall, leaves that to you. Breville recommends single wall for fresh-ground beans, because it lets you adjust those variables, and dual wall for pre-ground coffee.
Do pressurized baskets hurt espresso, and when should I switch?
We found no neutral taste comparison to settle the first part. What's documented is the job each one does. Switch to single wall once you own a grinder that can go fine enough and you want to dial in, since a dual wall basket smooths over the changes you'd be judging. Staying on pre-ground? Dual wall is what it's made for.
Will a VST or IMS basket fit my Breville?
The retailer page on VST and IMS's own page that we read both describe 58 mm baskets. Breville's Barista Express, Impress, Bambino and Bambino Plus use 54 mm portafilters, so those particular baskets won't fit them. A 58 mm Breville Dual Boiler is a different story. Measure your own basket, and check the seller's fit notes for your machine.
Does a bigger basket mean a stronger shot?
It means room for a bigger dose, and the basket's rated range tells you what to put in it. Strength then comes from your dose and yield, not from the basket's label. IMS gives different ranges by roast for one basket, so treat these numbers as a starting point and go by your scale and your cup.
What does ridgeless mean on an espresso basket?
A ridged basket has a retaining ridge that locks it into the spring in the portafilter, which one retailer calls the traditional design. A ridgeless basket drops that ridge. Whether a ridgeless basket stays put in your portafilter depends on the design, so check the seller's notes for your machine before you order one.
Where this comes from
- Breville: Barista Express instruction book (copy hosted by Williams-Sonoma)
- Breville: Bambino instruction book (US, Canada, Mexico)
- Breville: BES500 Bambino Plus product page
- IMS: B702TH24.5M filter basket
- iDrinkCoffee: VST Precision Basket, 18 gram standard (retailer)
- Smeg: EMC02 espresso machine, US page
Next round
PortafiltersWhat a portafilter is and which size your machine uses: 51, 53, 54 or 58 mm by model, with the source named, why millimeters alone don't prove fit, and when to buy.- Espresso doseHow many grams of coffee for espresso: dose by basket. Breville's 8 to 11 g and 16 to 19 g baskets, its 18 to 22 g start, and why Italy's standard says 7 g.
- Bottomless portafiltersA bottomless portafilter shows you channeling, and it doesn't improve the shot on its own. What it reveals, what it hides, how to check the fit, and what to expect.
- Puck prepEspresso puck prep in six steps: dry, weigh, stir, settle, tamp level, lock in. What channeling is, which tools have evidence, and what a wet puck means.
- TampersWhich espresso tamper fits your machine: 51, 53.3, 54 and 58 mm by model, what calibrated and spring-loaded tampers really do, and where the 30 lb figure comes from.
semiautomaticespressomachine.com Editorial Team
Espresso gear & shot craft
We are the editorial team at semiautomaticespressomachine.com. We read maker spec sheets, manuals, standards and published research on espresso and turn them into plain-English buying advice, with sources on every page. We do not run lab tests, and we say so openly.
- Spec sheets & standards read
- Sources on every page
- No lab tests – stated openly
- Publisher details in the imprint