Precision curve for espresso

Find precision baskets for espresso from IMS in various sizes, heights, and capacities. A precision-engineered filter basket provides a uniform starting point for extraction and makes it easier to work consistently with dosage, grind size, and brew time.

Choose your basket based on your espresso machine, the portafilter measurements, tamper size, and the amount of coffee you typically use. You will find models with a ridge, ridgeless models, as well as baskets with a flat or convex base.

Which IMS precision basket should I choose?

The various models in the range differ primarily in tamper size, height, base shape, ridge, and capacity.

IMS B702TCH24E – 58 mm, H24

The B702TCH24E is a ridgeless Competition basket with a convex base for a 58/58.4 mm tamper.

At 24 mm, it is the lowest of the three convex B70 models in our current selection, making it suitable if you work with a relatively smaller espresso dose.

IMS indicates different capacities depending on the roast degree and density of the coffee, so always use the manufacturer's values as a starting point rather than an absolute dosing rule.

IMS B702TCH26E – 58 mm, H26

The B702TCH26E has the same basic convex and ridgeless construction but is 26 mm high.

It thus provides room for a larger dose than the H24 model and can be a good middle ground if the H24 is too small, while the H28.5 provides more capacity than necessary.

IMS B702TCH28.5E – 58 mm, H28.5

The B702TCH28.5E is the tallest of the three convex models in our current selection.

It is also ridgeless, uses a 58/58.4 mm tamper, and provides room for larger doses.

In particular, verify that your portafilter has sufficient depth for the 28.5 mm high basket.

IMS B702TH24.5M – 58 mm, H24,5

The B702TH24.5M differs from the convex E-models.

It uses an M-pattern, has rounded internal corners, and an external ridge that the portafilter's spring can grip.

It also uses a 58/58.4 mm tamper.

This makes the model interesting if you prefer a classic Competition construction with a ridge rather than the ridgeless convex models.

IMS B652TH27.5M – 53 mm, H27,5

The B652TH27.5M is the relevant model in our range if you work with a 53 mm tamper and a compatible B65 portafilter.

The basket is 27.5 mm high, has an external ridge, and uses the IMS M-pattern.

Please note that a 53 mm tamper size alone does not guarantee compatibility. Also check the border diameter, the basket body, the height, and your specific espresso machine or portafilter.

Prioritize compatibility – then capacity

The best order is:

Portafilter and compatibility → tamper diameter → basket height and capacity → ridge/ridgeless → base shape and perforation pattern

This way, you avoid choosing a technically interesting filter basket that does not fit your espresso setup correctly.

How to read the model number of an IMS filter basket

IMS uses model numbers like B702TCH24E and B702TH24.5M to describe the filter basket construction.

The codes may look technical, but several parts tell you something specific about the basket.

Take, for example, B702TCH26E:

B70 indicates the basket's border diameter and is thus an important part of the compatibility with the portafilter.

2T indicates a basket for 2 cups – i.e., a double basket.

C indicates, in this series, a cylindrical basket with a convex base.

H26 means that the basket is 26 mm high.

E indicates the perforation pattern in the base.

The model number is therefore more than just a product code.

When comparing IMS baskets, you should also check:

• Outer diameter
• Body diameter
• Height
• Tamper size
• Ridge or ridgeless
• Base shape
• Recommended dosage

Two filter baskets can look almost identical and still have different dimensions and compatibility.

E- or M-perforation – what does it mean?

The letter at the end of several IMS model numbers describes the perforation pattern used in the base of the basket.

E-pattern

The IMS E-pattern uses a hexagonal hole pattern.

On the B702TCH series, up to 715 holes are used with a perforated area of up to approximately 49 mm.

The E-pattern is found, among others, on the convex B702TCH24E, B702TCH26E, and B702TCH28.5E.

M-pattern

M-pattern is IMS' Micro-pattern and uses a denser rectangular hole pattern.

Here, up to 641 holes are used over a smaller perforated area of up to approximately 44 mm.

You will find the M-pattern on, among others, the B702TH24.5M and B652TH27.5M.

This does not mean that E is automatically better than M – or vice versa.

The basket's overall construction, diameter, height, capacity, base shape, and compatibility should carry more weight than the letter in the model number itself.

When you switch filter baskets, you should also be prepared to adjust your grind size and potentially the rest of your espresso recipe.

The precision basket as part of your espresso setup

A precision basket works in tandem with the rest of your espresso workflow.

Use a tamper that fits your chosen filter basket precisely.

If you want to work with the distribution of the ground coffee before tamping, you will find our WDT tool.

A coffee scale makes it easier to keep both the dose and final espresso yield stable when you adjust your recipe.

Also, see our full selection of espresso equipment and coffee beans for espresso.

Ridge or ridgeless?

A filter basket with a ridge has a retaining groove that the portafilter's spring can grip. It helps keep the basket securely in place, for example, when knocking out the used coffee puck.

A ridgeless filter basket has smooth sides without this groove. This provides an unbroken inner wall and simultaneously removes a groove where coffee oils and fine coffee particles might otherwise accumulate.

The difference is largely practical. Both types can work well when the basket fits the portafilter correctly.

How securely a ridgeless basket sits depends, among other things, on the portafilter spring.