All I have read about PID is about the Rancilio Silvia and very exceptionally about Gaggia.
I understand what it does, even read how it is done. What I'm wondering is why it's so popular for the Silvia and not for the other machines. Is the Silvia inferior in that regard or simply a machine that attracts tinkerers.
I'm learning that espresso making is VERY time consuming. I started only a 3 months ago and have spent at least 1 to 2 hours a day reading here and elsewhere on the net. Learning but still have a lot of questions.
Thanks Colin for your site and to the peoples who contribute to the forums.