another_jim wrote:The expert consensus is that any tamp or none, consistently applied, works. The real trick is to distribute and level the grinds perfectly, paying special attention that there are no gaps around the edge.
Tamping is less important than distribution which is less important that consistent dosing.
All that matters with tamping is that:
a) you preserve the bed of evenly distributed coffee,
b) you do so in a consistent manner shot to shot.