IMS Competition Precision Filter Basket 58 mm Convex H28.5

Get a more precise and consistent foundation for your espresso with the IMS Competition B702TCH28.5E. Developed for larger double espresso doses, this filter basket combines a cylindrical shape with a convex bottom and 715 precision-manufactured micro-holes.

The convex bottom directs the brewed espresso toward the center of the basket, making this model particularly suitable for use with a bottomless portafilter.

Convex bottom for centered flow

Unlike a traditional flat filter basket, the B702TCH28.5E has a slightly curved base. The shape concentrates the flow toward the middle of the basket, creating a centered stream of espresso.

The convex construction is designed to:

• Utilize the entire coffee puck during extraction

• Gather the flow toward the center of the basket

• Provide a clear flow in a bottomless portafilter

• Support drying of the coffee puck

• Make the used puck easier to knock out

The shape of the basket alone cannot prevent channeling. Uniform grinding, proper distribution, and level tamping remain essential.

715 precision-manufactured holes

The basket bottom features 715 holes with a diameter of 0.30 mm. The holes are arranged in a hexagonal pattern over a 49 mm perforated area.

As part of the IMS Competition series, the perforation is post-processed and calibrated to create a more consistent size and shape for the holes.

This provides a stable starting point when adjusting:

• Grind size

• Dosage

• Brew time

• Yield

• Brew ratio

A precision basket can therefore make it easier to replicate a good recipe and identify the effect of individual adjustments.

Large capacity due to height

The filter basket is 28.5 mm high and is designed for relatively large doses. IMS indicates different capacity ranges depending on the roast level of the coffee:

• Dark roast coffee: approximately 19–22 g

• Medium roast coffee: approximately 22–25 g

• Light roast coffee: approximately 23–27 g

The difference is due in part to the fact that light coffee beans typically have a higher density and therefore take up less space at the same weight than dark-roasted beans.

The dosages are indicative. The correct amount also depends on grind size, coffee density, and the clearance between the coffee puck and the machine's shower screen.

For 58 and 58.4 mm tampers

IMS specifies the filter basket for tampers with a diameter of 58 or 58.4 mm. A snug-fitting tamper helps compress the coffee evenly all the way to the edge of the basket.

The basket dimensions are:

• Outer rim: 70 mm

• Basket body: 60 mm

• Height: 28.5 mm

• Recommended tamper: 58–58.4 mm

The designation 58 mm does not automatically mean that the basket fits all 58 mm espresso machines. The portafilter must also have the necessary internal diameter and depth.

Therefore, always compare the dimensions with your existing filter basket before purchasing.

Ridgeless construction

The B702TCH28.5E is ridgeless and therefore has no external retention groove.

The smooth exterior makes the basket easier to insert and remove from the portafilter. How firmly it sits depends on the portafilter's spring and construction.

A ridgeless basket can still be held securely by the portafilter spring, but the fit should be checked before use.

Electropolished surface

The filter basket has an electropolished and passivated surface. The treatment reduces microscopic imperfections and creates a smooth surface that is easier to clean.

The smooth finish helps limit the buildup of coffee oils and fine coffee particles, but the basket must still be cleaned regularly.

Particularly suitable for bottomless portafilters

The convex bottom gathers the espresso toward the center and therefore pairs well with a bottomless portafilter.

A bottomless portafilter also makes it easier to observe:

• Whether the flow starts evenly

• Whether the espresso gathers toward the center

• Whether channeling occurs

• Whether the tamping is uneven

• Whether puck preparation should be adjusted

The filter basket can also be used in compatible spouted portafilters if there is sufficient space under the basket's convex bottom.

How to achieve a good result

1. Choose a starting dose that fits the coffee's roast level.

2. Distribute the ground coffee evenly in the basket.

3. Optionally use a WDT tool to break up clumps.

4. Tamp the coffee horizontally with a suitable tamper.

5. Check that there is space between the puck and the shower screen.

6. Brew the espresso and evaluate the flow, time, and taste.

7. Adjust primarily the grind size while keeping the dosage stable.

It is recommended to start at the lower end of the suggested dosage range. An overfilled basket can cause the coffee puck to hit the brew head and affect water distribution.

Cleaning and maintenance

Knock out the coffee grounds after brewing and rinse the basket thoroughly with hot water. Check regularly that the 715 holes are not clogged by coffee oils or fine particles.

For deep cleaning, the basket can be soaked in a suitable cleaning agent for espresso and coffee equipment. Follow the cleaner's instructions and rinse the basket thoroughly with clean water afterward.

Avoid needles, steel brushes, and other sharp tools that can damage or alter the shape of the micro-holes.

Specifications

• Brand: IMS

• Series: Competition Convex

• Model number: B702TCH28.5E

• Product type: Precision basket for espresso

• Capacity: 2–3 cups

• Height: 28.5 mm

• Outer rim: 70 mm

• Basket body: 60 mm

• Tamper size: 58–58.4 mm

• Bottom: Convex

• Retention groove: No – ridgeless

• Number of holes: 715

• Hole diameter: 0.30 mm

• Perforated area: 49 mm

• Hole pattern: Hexagonal

• Surface: Electropolished and passivated

• Suggested dose, dark roast: 19–22 g

• Suggested dose, medium roast: 22–25 g

• Suggested dose, light roast: 23–27 g

• Portafilter included: No

• Tamper included: No

The IMS Competition B702TCH28.5E is an obvious choice for the espresso enthusiast who wants a large, ridgeless, precision basket with a convex bottom, centered flow, and room for larger doses.

Frequently asked questions

How much coffee fits in the IMS B702TCH28.5E?

IMS indicates approximately 19–22 g for dark roast coffee, 22–25 g for medium roast coffee, and 23–27 g for light roast coffee. The optimal dosage also depends on grind size and coffee density.

Which tamper fits the basket?

The basket is intended for tampers with a diameter of 58 or 58.4 mm. A snug-fitting tamper usually provides the most uniform tamping along the edge of the basket.

Does the basket fit all 58 mm espresso machines?

No. You must also check the basket's outer rim of 70 mm, the body diameter of 60 mm, and the height of 28.5 mm. Furthermore, the portafilter must have room for the convex bottom.

What does the convex bottom mean?

The convex bottom is slightly curved and directs the finished espresso toward the center of the basket. The shape pairs particularly well with a bottomless portafilter.

What does ridgeless mean?

Ridgeless means that the basket does not have an external retention groove. The smooth exterior makes the basket easier to remove, while the portafilter spring can still keep it in place.

How many holes does the filter basket have?

The basket has 715 precision-manufactured holes with a diameter of 0.30 mm.

Does the basket prevent channeling?

Not on its own. The basket's uniform perforation provides a precise foundation, but correct grind size, distribution, dosage, and level tamping remain essential.

Can the basket be used in a spouted portafilter?

Yes, if the portafilter has sufficient diameter and depth for the basket's height and convex bottom. Always compare with the dimensions of your current basket.

Are a portafilter or tamper included?

No. The product consists only of the IMS filter basket. Portafilter, tamper, and other espresso equipment are purchased separately.