As has been stated many times... The issue of Tamp pressure is one of *Yes and NO.. *
It is about being consistent and is dependant on ya beans and the grind etc etc..
I dont think I have used more than a few Kg in Tamp pressure for some time... *Unless the coffee is getting old and stale or I have used too course a grind... Then I compensate with my TAMPING...
People need to realise it is not about 18g, 20g or 21g of coffee in a 58mm basket and 15kg of tamp pressure... :P
The coffee is not consistent and unless you have a partical sizer you can only guess by feel as the the grind size...
It is about understanding all the variables and knowing that by making adjustments across a number of things, that you have control in; you can some times get a cup of coffee nectar that is to die for.. *;D
There is no *1 + 2 + 3 = Coffee.... * It is more about 2 + 2 = 5 depending on teh exact value of the 2s *:o