This is a tricky question, and we get it ; Aluminum is not a safe material so how could we use it?
Aluminum contamination in grinders occurs as the grinder degrades. While traditional grinders doesn't have a buffering surface between the main grinder parts, our grinder does ; it is our main feature. see, friction is accelerated when the 2 materials having the same molecular structure, they can bond easily, leading to wear down - a sticky grinder. Our Aluminum is coated using an organic, PIGMENT FREE coating which increases the surface layer hardness - which increases the molecular structure diversity between the FRICTION REDUCTION RING and the main grinder parts to reduce the friction of the grinder.