How to Choose a Coffee Machine For Pods Pod machines operate by reading the barcode at the top of the pod (which is actually an un-sealed disc of pre-dosed ground coffee that is pressed between two layers of filter paper). Simply insert it into the machine and push a button. https://www-coffeee-uk83762.educationalimpactblog.com/50649965/a-positive-rant-concerning-best-pod-coffee-machine