JavaGrind manual hand coffee grinder has two unglazed ceramic cones that snugly fits together. The casting of the ceramic is fairly course so as to avoid making edges sharp.  The grinder comes with a knock down handle especially designed to fit GSI JavaPresses and Mugs. the ceramic burr are adjustable and produce uniform grind. When it grinds it does not leave too much sediment in the bottom of the cup. If freshly roasted coffee beans used for grinding, the coffee powder is not too acidic on the contrary it has a very smooth finish.