What is a Group Head?
Also referred to as the brew group or brew head, this component is more commonly known simply as the group. This is where you insert the portafilter when preparing to brew espresso. The group head is equipped with "notches" where the portafilter locks into. When in use, the portafilter is positioned up into the group head and then turned to lock-in.
How Many Group Heads Do I Need?
Commercial Espresso machines are always defined by the number of group heads that they have. Why? Well - simply because it is a big determining factor of the volume and output that a machine can do. A one-group machine means that you can only have one barista working on that machine at a given time. We've found that 2-group and 3-group heads are the most popular. At home, you really only need one.