As a training tool, the bottomless portafilter is excellent for checking your tamping technique. Increased crema, better mouthfeel, and it’s just tastier. Bottomless portafilters allow you to see the espresso as it exits the basket. This allows you to immediately identify any faults in your dosing or tamping technique. You may be tamping slightly unevenly without releasing it; with a 51mm bottomless portafilter you will see espresso leaving one side of the basket before the other side instead of it appearing evenly,something which would be impossible to gauge with a spouted portafilter. What Is Channeling? When you tamp your well-dosed grounds evenly inside the portafilter, you’ll force the water to seep uniformly through the puck, resulting in a balanced extraction. But if you rush the tamping process, your puck will have varying levels of compactness and resistance. This is bad because water will only pass through the areas, or “channels”, that have the least resistance. If this happens, you’ll be left with a chaotic cup that has both under-extracted and over-extracted tones. A Bottomless Portafilter can prove very useful in identifying channeling You can evaluate the number of channels, their direction, orientation, speed, etc. Then, you can use this data to reflect on your process. For instance, a large number of channels over the peripheries suggest that your tamper doesn’t exert enough pressure in that area. As the shot pulls, you can see the droplets of espresso forming on the bottom of the basket. You can then see the stream flowing down into your cup. It’s incredible! Be your own Barista with a La Specialista bottomless portafilter. For De'Longhi La Specialista: EC9335 EC9155 EC9665 EC9355 Product Feature Material: 18/8 Stainless Steel(#304), Wooden Handle Weight: 330 g Size: 51mm portafilter with 25g filter basket