it depends on the bean, how old it is, the humidity, your machine etc. It'll be hard/impossible to get a great espresso shot from a lot of machines as they jus

it depends on the bean, how old it is, the humidity, your machine etc. It'll be hard/impossible to get a great espresso shot from a lot of machines as they just don't have the power. Compound that with the quality of grinder. Some beans are very forgiving and give a decent espresso with a wide range of parameters. Some beans are very picky on getting the settings right. I've had a range of machines - and my current machine is the only one that I can get a decent cup from (BES920). To your question, you need to adjust depending on the output from your machine.