Grinding, dosing, and tamping
Espresso is sensitive to the relationship between grind size, coffee amount, and brew time. The grounds need to be fine enough to create resistance to water, but not so fine that water barely passes through. With a manual or semi-automatic machine, you grind coffee, place it in a portafilter, which is the handled basket that locks into the machine, distribute the grounds, and tamp them level. Small inconsistencies can change the result from one shot to the next. At first, this process can take several minutes and produce some discarded shots while you learn what your machine and beans need. It becomes faster when you use the same basket, dose, and grinder setting regularly. A machine with a built-in grinder or guided dosing can reduce measuring steps, but it does not remove the need to keep the grinder clean and adjust it when coffee behaves differently. If weekday mornings are rushed, plan for a simpler drink or use a drip brewer as a backup.
