Coffee grinder for grinding coffee beans, comprising a container or supply element for coffee beans and a grinding device for grinding the coffee beans. The grinding device comprises a first and a second grinding element between which the coffee beans are ground, the distance between the two grinding elements in the grinding process determining the degree of grinding of the ground coffee, and at least one grinding element being driven by a motor. An adjusting element is provided, with which the distance between the two grinding elements can be adjusted by rotating an adjusting element, and a magnetic rotational position sensor, which directly or indirectly determines the absolute rotational position of this adjusting element as a measure of the distance and provides it for the further control of the coffee grinder.