Which part locks into the espresso machine to begin extraction?

Which part locks into the espresso machine to begin extraction?

• A. Portafilter
• B. Hopper
• C. Dosing chamber
• D. Grinding burrs

Answer: (A)

The key idea is creating a tight seal between the machine and the coffee bed so water can be forced through under pressure. The portafilter is the part that locks into the group head, holding the ground coffee in a compact puck. When you twist it into place, it seals the path for hot water to flow through the puck and begin extraction. The other items—the hopper stores beans before grinding, the dosing chamber holds measured grounds, and the grinding burrs grind the beans—do not participate in locking into the machine to start extraction. Without a securely locked portafilter, you’d lose pressure and risk leaks or uneven extraction.

The key idea is creating a tight seal between the machine and the coffee bed so water can be forced through under pressure. The portafilter is the part that locks into the group head, holding the ground coffee in a compact puck. When you twist it into place, it seals the path for hot water to flow through the puck and begin extraction. The other items—the hopper stores beans before grinding, the dosing chamber holds measured grounds, and the grinding burrs grind the beans—do not participate in locking into the machine to start extraction. Without a securely locked portafilter, you’d lose pressure and risk leaks or uneven extraction.