Automatically adjustable coffee grinder for a coffee brewing system

A grinder for grinding whole coffee beans into coffee grounds with automatically adjustable coarseness, comprising:

• a burr assembly for grinding whole coffee beans, comprising:
• an inner burr having a side surface that is slanted and abrasive or serrated;
• and
• an outer burr surrounding the inner burr, wherein the side surface of the inner burr and the outer burr define a gap;
• a main motor configured to provide a first rotational movement to the inner burr;
• a main shaft having one end attached to the inner burr, wherein the main shaft is configured to transfer the first rotational movement provided by the main motor to the inner burr;
• a second motor configured to adjust a vertical position of the main shaft and the inner burr relative to the outer burr, wherein changes in the vertical position of the inner burr relative to the outer burr cause changes in the gap between the inner burr and the outer burr;
• and
• a controller configured to control the main motor and the second motor;
• wherein a coarseness of the coffee grounds depends on the gap between the inner burr and the outer burr.