I've only ever used two manual grinders with flat burrs. The other one is Fiorenzato's Pietro grinder, which is unwieldy, to say the least. I found this one, and bought it to try at home. I opted for 48.6mm ghost burrs because they are unusual, and are supposed to produce more rounded grinds, rather than the longer, shaved pieces produced by normal burrs. That feature makes for a more uniform bed of grounds in a pourover dripper, which should yield a more even extraction. Ghost burrs were invented in Japan in the 60s, and have been in widespread use for drip grinders there. It's fairly rare to see them in the US even today.
The first thing I noticed about this grinder is the bearings, which are a solid feature, obviously imperative with use of flat burrs, and ghost burrs specifically. I was curious how the grinder would function, because flat burrs always feed horizontally, with the burrs oriented vertically so the ground coffee can drop out from the space between burrs. This grinder also feeds from the center of the burrs, pushed with a tiny auger mounted to the bottom burr, and drops the grinds from 360 degrees around the perimeter. In a conical burr grinder, the coffee is squished between the fixed outer ring burr and the inner cone-shaped burr - the whole system designed for a vertically oriented drive shaft. So it's a wonder that this actually works, but it does. It's ingenious really. The bottom burr is held in place by a slotted washer that fits on the end of the shaft, with a pin that goes into a hole in the burr carrier, then held in place with a stepped adjustment knob. If that weren't enough, the burr set is coated with titanium, making the edge retention and lifespan much longer than uncoated steel burrs.
Other than that, it operates just like any other manual grinder you've ever used. If you didn't know what was going on inside, you might be fooled into thinking this was your run-of-the-mill grinder. But it's not. And whenever someone asks you about it, you get to say "Ghost burrs."
Comes with a carrying case, brush, and bellows to puff out any retained grounds.
