I tested that once on an old Black+Decker burr grinder by changing the OEM ungrounded plug to a grounded one. The superstructure was mostly plastic so grounding

I tested that once on an old Black+Decker burr grinder by changing the OEM ungrounded plug to a grounded one. The superstructure was mostly plastic so grounding the whole unit wasn't possible, so I attached a length of grounded bare copper wire and ran it into the hopper after drilling a tiny hole (which made the polystyrene crack and require gluing). The results were not as I hoped: the bare wire thankfully seemed to conduct a lot of the static, but that meant the copper wire was coated in the grounds. The end result was that empthing the hopper was pretty well just as messy as without grounding. Your results may/will vary, and I never attempted other grinder grounding ideas. I bought a KitchenAid KCG8433DG, which does not have any issues with static.