Commerical 2 - 4.5 gram / second
3. Ventilation passive or active to take the motor heat out of the encasement, there is enough heat caused in the friction of the espresso coffee beans in between of the burrs to take care of.
4. Quality and durability of course.There are many espresso coffee grinders on the market, most of them either lack the quality we expect or they are too expensive for what they can do for you. Please call us to help you to find the right size and whether doser or on demand: 800 746 6174