Fundamental 6 of 6
Contact time
Contact time is how long water is in contact with the coffee during the shot — usually the total shot time. It's the result of your grind, dose and pressure working together, not a dial you set directly. A wildly short or long time signals something upstream is off.
Quick cue
A 1:2 shot landing roughly in the 25–35s range is a healthy sign. Off that? Adjust grind.