As you know there are different ways to extract different types of shots (i.e. Ristrettos and lungos) that takes some practice. Maybe go over espresso blend components. Start them on latte art basics like easy hearts and apples. Those were the first things that came to mind.
I always include advanced maintenance in my 201 class; taking apart the grinder, backflushing the machine, etc. Also I break down shots pulled into 5 second intervals and have them taste at each to emphasize the different components. Advanced discussion of milks and the differences in steaming. Also I teach sharing a bar, splitting duties so when two people are making drinks during a rush it's not chaos.
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