If you have read my review of the KitchAid ProLine Grinder, you will learn about my dissatisfaction with the machine's ability to grind truly fine and uniform particles of coffee.

This failure I attribute to poorly manufactured burrs, seeming made out of soft metal that could not keep a sharp edge.  After several tens of hours use, my KitchenAid grinder produced something that looked like I had chewed it with my own molars" chunky, uneven grinds that would all water to bypass the coffee and pass through the filter.

I mentioned that I had bought a new set of burrs for this machine.  After a good cleaning I installed the burrs.  Replacement was simple, just a couple of screws per plate.

The results were better, but not what you'd expect from a $300-plus (as of December, 2022) coffee grinder.  Uniformity had returned to the grind, which is a good thing. But do not expect this appliance to provide a very fine grind for espresso.  The replacement burrs seem to be made of the same soft metal as the originals, so I expect the grind to become more coarse as time wears on.

The KitchenAid is a beautiful and nicely constructed machine.  The burrs are a failure and disappointment. You can do much better in this price bracket.