The 5 Star Pro features two stainless steel components at its base. The upper component is a leveling flange, shaped like a star, that rests on top of the filter basket. This plate ensures a level tamp by maintaining a vertical alignment as you press down. Its hollow sections allow for easy alignment within the basket and help remove residual coffee grounds that may collect between the leveling plate and the base.

The lower component, known as the compression flange, applies pressure to the ground coffee as you push the handle down. The flanges can be customised to fit various filter basket sizes, such as 52mm or 58.4mm, and are available in thicknesses of 5mm or 7.5mm.

Pressure is controlled by a pre calibrated spring inside the tamper. When installed, the spring is placed under pressure. For instance, a 10kg spring is secured by a steel pin and is compressed to 7kg of pressure. As the handle is pushed down, the spring compresses 3mm to achieve the full 10kg pressure by the time the handle meets the base of the tamper. Similarly, a 15kg spring is set to 10kg of pressure and compresses to 15kg when fully engaged. 

With springs available in 7kg, 10kg, and 15kg, you can adjust the pressure to your preference. These springs are interchangeable to suit your needs.

Additionally, a larger spring ensures that the leveling plate returns to its original position after tamping, though it does not affect the pressure applied to the coffee.

The 5mm base achieves a tamping depth of approximately 14mm inside a filter basket, while the 7.5mm base reaches a depth of around 16.5mm (ideal for VST or IMS filter baskets).

Each tamper includes three specially calibrated springs: a silver 15kg spring, a red 10kg spring, and a blue 7kg spring. The 7kg spring is especially suited for home baristas using older domestic coffee machines with less powerful internal water pumps. For commercial coffee machines or newer one-group home machines, we recommend using the 15kg spring.

When the springs are inserted into the tamper assembly, they are placed under pressure. To achieve the pre-calibrated pressure, the spring compresses 3mm inside the assembly.

For instance, with the 10kg spring installed, it is initially under 7kg of pressure. As you push the handle down, the spring compresses by 3mm, reaching a final pressure of 10kg when the handle meets the base of the tamper.

Similarly, the 15kg spring starts under 10kg of pressure. As you push the handle, the spring compresses 3mm, achieving a final pressure of 15kg. This allows you to achieve a compression range of 7 15kg, depending on the spring used.

Changing the spring is straightforward and can be done with a 12mm or similar spanner. If you need one, you can purchase it from our accessories page. 

For a demonstration on how to change the spring in a 5 Star Pro, please click on the video here.

Since we began manufacturing in 2007, we have never received a request to replace a spring. This is because the spring remains under constant tension within the tamper, with only a 3mm movement. To put it simply, it's akin to using a heavy duty truck spring in a small car—it's designed to last and won’t wear out.

If you’re using VST, IMS, or other competition filter baskets (typically sold separately from coffee machines), and you dose according to the recommended amount for each filter basket, such as 18g in an 18g basket, we recommend the 7.5mm thick compression base. This base is also suitable for standard filter baskets that come with coffee machines.

For filter baskets with a diameter of less than 51mm, the 5mm thick base is recommended.

To determine the appropriate base thickness, measure the depth between the top of a compressed coffee puck and the top of the filter basket. If you’re not dosing according to the basket's recommended dosage, it’s a good idea to take this measurement before selecting your base.

Additionally, the thickness of the compression base may vary depending on the density of the coffee you use.

Since the 5 Star Pro base compresses vertically inside the filter basket, a base slightly larger, such as 58.5mm, is generally compatible with a 58mm filter basket. However, we cannot guarantee this compatibility.

Customers are responsible for ensuring they choose the correct size base for their needs.

The infusion base alters the coffee’s flavour profile compared to the flat base. The impressions made by the infusion base promote pre-brewing at the start of extraction, which affects the coffee’s flavour and acidity.

In our testing, we found that the infusion base often produced a sweeter taste. However, the exact impact will vary depending on the coffee blend or roast used.

Visit our Tamper Size page
or check if your coffee machine manufacturer provides basket dimensions for your model online.

If you use multiple filter baskets or coffee machines with different basket diameters, we recommend purchasing bases that match those sizes and can be interchanged as needed.

You can also review available base options on our product pages. We are also available to discuss base sizes in more detail. Please note that selecting the correct base size is the customer's responsibility.

Yes, we offer sizes ranging from 49mm to 60mm in diameter. If you require a size that is not listed, please contact us before placing your order. Be sure to note your desired size in the comments section during checkout. Please note that selecting the correct base size is the customer's responsibility.

No, the small markings on the base of the tamper are simply a result of the manufacturing process. Each tamper will have some sort of mark due to the stainless-steel material. Our stainless-steel bases are machined using a lathe, and when they are removed from the lathe, they are placed in a basket with other bases. This can cause minor markings. These imperfections do not affect the quality of the tamping and have no impact on the flavour or consistency of the extraction.

Yes – our acetal handles are hand turned, not injection moulded. These lines are a normal by-product of the manufacturing process.