A grinder (100) comprising an inlet orifice (110), a grinding device (120) for grinding coffee beans, and a discharge orifice (130), the grinding device being arranged to receive the coffee beans via the inlet orifice (110), to grind the coffee beans, and to discharge ground coffee via the discharge orifice (130), the grinder comprising a dispenser (140) arranged to dispense a controlled amount of electrically conductive additive such that the electrically conductive additive contacts the ground coffee.