I really enjoyed the hot chocolate made by this machine and was keen to investigate. It turns out that the stirrer is held in magnetically. There must be a rotating magnet or some kind of induction motor effect in underneath. Previously there would have been a sealed spindle up from the motor below but that would still have left joints down which liquid could seep. I first saw magnetic stirrers in the lab nearly 30 years ago so it is interesting to see that they have now made it into the kitchen.