Tamper base "Base Convex" 57mm

Why the name Knock?
After the first tamping of the espresso, lightly tap the side of the portafilter. "knock", which causes all the espresso powder to fall sideways from the edge into the portafilter. Then it's tamped again. So that the tamper base does not have to be used for this light tap on the portafilter, which could damage the soft portafilter or even the wooden handle, the silicone ring integrated into the base can now be tapped. We have had this invention protected by law.
Why Convex?
Normally, the surface of the espresso tamped in the portafilter does not play a major role; Whether flat (flat) or convex (arched), there is enough space between the espresso surface and the shower sieve so that the water can be evenly distributed over the espresso and the espresso powder can penetrate evenly. However, if flat sieves are used or significantly more than 7g (1-cup sieve) or 14g (2-cup sieve) are used, there may not be enough space between the espresso powder and the shower sieve for optimal distribution of the brewing water. A Tamper Base Convex can be used for this purpose, leaving a hollow in the middle for better water distribution.