Unlock new dimensions of flavour with the INTROVERT 58mm to 49mm stepdown espresso basket, designed for clarity, balance, and shot stability.

What is a stepdown espresso basket?

A stepdown espresso basket fits a standard 58mm portafilter but has a smaller extraction chamber, 49mm for this instance. Given the same dosage size, this results in a thicker espresso puck and promotes more balanced shots, more even extraction, more even flow, and ideally more pronounced flavours with less harshness as a result.

By having a taller aspect ratio espresso puck, you rely more on the thickness of the coffee puck to provide its own resistance rather than choking it with a finer grind on a thinner puck. With the coarser grind afforded by the thicker puck, you decrease the chances of channeling, dry spots, and uneven extraction that usually results in harshness, astringency, and bitterness. Overall, it brings the forgiving, high-aspect-ratio performance of 49mm baskets to your 58mm machine, and makes low-dose and precision shots easier and more consistent.

Current Status

All pre-orders of Beta baskets and the Premium Accessories Bundle, the 58-49mm Stepdown Dosing Ring, or the 58-49mm Tamper, have been shipped.

58-49mm Beta V0.5 Edition Basket

Following the successful launch and feedback stages of the Alpha V0.1, I launched the Beta V0.5 version in October 2025. The Beta version focuses on the following:

Greater compatibility for a wider range of shower screens and dispersion blocks by increasing its 58mm zone diameter
Additional flow rate options (+Low flow, +High Flow)
Additional capacity option (+Dedicated 16-18g version)
Maximizing workflow smoothness with improved accessories

Being a Beta design, there may still be some unexpected minor issues with the basket. Just as the Alpha feedback is shaping the future versions, your feedback will help refine the final production model, giving you a chance to shape the future of espresso gear.

Additionally, having a large sample size with various machines, portafilters, and workflows will help ensure that it is more compatible with more setups!

Please keep in mind that every single aspect and detail of the basket and accessories may be subject to change in future iterations.

Follow the Beta progress on my blog

Key Features (Beta V0.5)

CNC-machined From a Solid Block of 304 Stainless Steel
Unlike almost all of the baskets out on the market, which are are stamped, this basket is CNC-machined from solid steel. This yields maximum precision, perfectly straight walls, much sharper and precise edges. The thickened base means it has little to no visible flex during the shot, up to 9 bars of pressure. Flexing during the shot will negatively affect consistency because the shape of the puck is actively changing and may focus the flow towards the center and, in the worst-case scenario, induces channeling. The straight walls and sharper edges allow for holes to be placed all the way to the edge, which allows for maximum extraction consistency (more explanation below: "Vertical Walls" and "Optimized Hole Pattern...").

Compatible with 58mm Portafilters
The upper portion of the basket before the stepdown fits standard 58mm portafilters and machines, just like other 58mm baskets. Due to the Beta design maximizing compatibility for various 58mm groupheads and shower screens, it's on the bigger end of diameters, so it may not fit some portafilter springs. It should also work with most 58mm dosing rings, most 58mm puck/mesh screens, and 58mm catch cups. However, using 49mm puck/mesh screens would be more optimal, which are accessories that I also sell.

49mm Extraction Zone
Focuses flow through a 49mm diameter extraction zone, enhancing clarity and balance. Pairs well with manual 49mm tampers. If you use 3rd party leveled tampers, they need to have extra long reach. My custom Self-Leveling Tampers from the Premium Accessories Bundle will fit either directly on the basket or on the custom Stepdown Dosing Ring.

Vertical Walls

The perfectly vertical basket walls mean that there is no diameter change throughout the entire extraction zone, and therefore not forcing any pressure changes the deeper down the basket it goes. Note that your tamper or puck/mesh screens will fit the same at any depth. One difference in workflow you will find vs other stamped or tapered baskets is that the spent puck will be more stubborn to get out. It will need more knocks or harder knocks to get the puck out, or you can use the Silicone Bellows For Single Dose Hoppers / Niche Bellows to effortlessly pop it out from the bottom.

Angled Step Down
While a dosing ring would help with dosing into the 49mm zone, the basket can still be dosed without it. The angled step down ensures that all coffee grounds will easily and satisfyingly fall down to the 49mm zone without getting stuck at the ledge when you tap it or wiggle it around. The example shown below is an 18g dose of loose, untamped grounds fitting into the 20-22g basket.

Optimized for 16-18g or 20-22g Espresso (Beta V0.5)

The Beta edition comes in two different sizes, the 16-18g version and the 20-22g version. Actual capacity will vary with the bean type, roast level, and grind size used. When fully dosed in the 49mm zone, it should land within the denoted range. Lighter roast and/or finer grinds will more likely often fill up the basket at the higher end of the capacity range whereas darker roast and/or coarser grinds will fit the lower end of the capacity range.

16-18g (Medium Dose)

This size is optimized to fit 16-18g of coffee with less headspace and resulting standing water after the shot. The custom stepdown dosing ring is required to prep a dose of 16-18g, and you tamp through the dosing ring so that the resulting puck height is very close to the top of the 49mm zone.

20-22g (High Dose)

You can expect the same workflow on this size basket as the 16-18g version if you're dosing for 20-22g. However, this basket is more versatile and allows for lower doses as well, with the tradeoff of a lot of extra headspace. When dosing about 16-18g in this basket, the loose grounds can already mostly fit in the 49mm diameter zone, and you can tap to reduce it down to the 49mm zone, and then tamp without going through the dosing ring. Expect a lot of standing water at the end of the shot unless you have a machine with residual pressure after the shot or have a purge function. This basket, with the deeper depth, also allows for soup shots with coarser grinds.

Hole Design (Beta V0.5)

Maximum Hole Coverage For High Extraction
Precise laser-cut holes that are evenly spaced in a layout inspired by the Fibonacci sequence. The whole array stretches all the way to the absolute edges of the basket to promote maximum evenness and smoothness in flow because there's no change in diameter throughout the entire depth of the puck.

Various Hole Patterns For Different Flows

I'm offering 3 different flow versions for both sizes of the Beta V0.5 baskets.

Key Differences of Basket Editions:

Each basket edition has some key differences, outlined below.

Beta V0.5: Latest batch with a full suite of refinements and optimizations.

Beta V0.5 Blemished: These Beta baskets have more serious surface imperfections or scratches, small dents, or poorly polished, but are otherwise fully functional.

Pre-Beta Experimental: Micro-batch of one-of-a-kind prototypes for my own testing. These have a wide range of flow variants with some optimizations and fixes improving on the Alpha. While these baskets are fully functional, some flow variants may be highly situational. Some baskets may have holes that weren't fully cut through, and may have surface blemishes. No custom packaging box included, but will be sufficiently wrapped to protect it. The included starter bundle is equivalent to the one included for the Beta basket, but tailor-fit to these Pre-Beta Prototypes.

Alpha V0.1: Very first batch of baskets. Compatibility with shower screens/dispersion blocks is limited. See chart below. Please also note that included the starter bundle is equivalent to the one included for the Beta basket, but tailor-fit to the Alpha V0.1.

Alpha V0.1 SUBPAR: These baskets from the Alpha batch had some manufacturing flaws, such as but not limited to: holes that weren't fully cut through, major surface blemishes, and dents, but are otherwise still functional.

Beta V0.5 Compatibility With Espresso Machines / Shower Screens:

Machines

✅Argos Odyssey
✅Flair 58
✅Lelit Bianca V3
✅Gaggia Classic E24
✅Meticulous
✅Rancilio Silvia + Countersunk Screw Mod

Portafilters

✅Argos Odyssey Stock Portafilter
🟨Fellow Espresso S1 Stock Portafilter (Possible retainer spring issue: too tight)
✅Flair 58 Stock Portafilter
🟨La Marzocco Linea Micra Portafilter (Possible retainer spring issue)
✅Lelit Bianca V3 Stock Portafilter
✅Meticulous Stock Portafilter
✅MHW3Bomber Portafilter
✅Bottomless from Shades of Coffee UK

If it doesn't fit your portafilter, it may most likely be because of the retaining spring.

Alpha V0.1 Compatibility With Espresso Machines / Shower Screens:(No data on machines not listed, thus no guaranteed fit)

❌Breville Dual Boiler
✅ECM Synchronika E61
✅Flair 58
❌Gaggia Classic Pro (Will not fit stock dispersion blocks and some others)
✅IKAPE K2 Pro Portable Coffee Maker (58mm)
✅La Marzocco GS3 (Stock shower screen)
❌Lelit Elizabeth (Stock Shower Screen/Dispersion Block)
✅Modbar
❌Pesado 58.5 Shower Screen
❌Pasedo HD Shower Screen
✅Profitec Pro 800
❌Sage Dual Boiler
✅Synesso Mvp Hydra (2022 1Grp)
✅Victoria Arduino White Eagle
✅Victoria Arduino Eagle 1 Prima
✅Wendougee Data S

(Beta V0.5 likely to be compatible with all listed above)

Optional Premium Accessories Bundle can be purchased from a separate listing here

Every individual accessory is also available for purchase on its own, found on the Espresso Tools page.

Requirements (Not Included):

58mm bottomless portafilter
- The basket is taller than usual baskets, which means it will likely not fit on any portafilters with a closed bottom
Espresso machine with 58mm grouphead

Featured By The Community:

Slowpresso by Home Cafe By Charlie

Unboxing and shot by Pbrewinghouse

Used on Ikape K2 Pro by fused_visions

Timeline:

Follow the Beta progress on my blog

Disclaimers / Notes:

Please join this test at your own risk, as there is always a chance that the basket may not be compatible with your equipment, just like with the Alpha. I won't be able to provide refunds for it once I ship it out.

Original disclaimer for the Alpha V0.1 Version:

"With all that said, while I'm super excited to release this product, it is currently in Alpha state, which means it may not work optimally, and at worse, may not work at all. Every single aspect and detail of the basket and accessories may be subject to change in future iterations."

A note on US Tariffs:

Duties are be pre-calculated at checkout for orders destined to the US. For those who pre-ordered the Beta baskets with a higher duty rate at the time of order compared to the time of shipping, I will refund the difference in duties.

58-49mm Step-Down

58mm-49mm Stepdown Espresso Basket

Self-Levelling Modular Tamper

Premium Accessories Bundle For 58-49mm Stepdown Basket Beta V0.5 or Alpha V0.1

Stepdown Dosing Ring - Anodized Aluminum