Been very concentrated into espresso making for many years. I have developed a technique for tamping to get the desired ristretto I love (and need). Of course the grind is very fine and I am using a Baratza Forte and brew with a Profitec Pro700 machine.
I have searched many times all over the web for ways to get that rich, thick, complex ristretto that I have rarely had at a shop. Of great importance of course is finding the right beans to get to that ristretto. It is strange to me that the definition of ristretto, i.e. what actually arrives in the cup, has been lost and baristas can not be trusted to give me what I am looking for. the best examples and my targets were a cup I had once in Berkeley, CA, but way before that, in Venice, Italy.
So...the technique is my own invention and some, maybe most, out there will not think much of it. It surprisingly takes some practice to get the results; not as simple as it looks. For the open minded (and ristretto hungry) I submit to you all my technique.
The pictures attached show what I now describe: With the 14 gms of very fine coffee in your portafilter and leveled, just set the tamper lightly on top of the grinds. No need to push on the tamper. Then with your thumb and forefinger tamp lightly while moving where your digits hit on the base of the tamper, so that you are move your hand back and forth around the tamper, all the while tamping lightly. See the pictures.