The point I was making was slightly different. The original reason for the 30 # tamp was that for Schoemer it was a compromise between the 90 # in vogue then and a tamp that would work, but not cause carpal tunnel syndrome. In these forums there has been argument by competant users for anything from practically no tamp to much heavier than 30 #. Of all the "standards" this was one originally established as a practical balance between commercial and quality considerations. It is fine if someone wants to start there, but I find that the pressure and style of tamp needed varies substantially from machine to machine.

I have not noticed that before. I have several different machines, I use the same tamp with each. Each may require a different grind and/or dose with any particular coffee but I always use the same tamp. I am in the 'does not really matter' camp. If you tamp light or heavy is of little consequence, as long as you are consistent, and level. Now a days I tend to grind finer and tamp light, but that is just me.