I have a La Pavoni Pro, and noticed that I am a bit inconsistent with the crema. I have read this other post on crema and understand the freshness of the beans are the most important part, but I have noticed even with the same beans my crema is not the same. There are a lot of variables with the La Pavoni, tamp, grind, pull, temperature of the machine etc. What variables should I should focus on after considering the freshness of the beans?
You should make sure that the coffee runs through with at least 6 bar pressure. If your pressure is below that value, you won't get a crema. The recommended pressure for Espresso is 9 bar ± 1, according to the Italian National Espresso Institute.