What are the disadvantages of high-speed grinding for matcha?

Heat Generation: High-speed grinding generates significant heat, which can damage sensitive components in matcha (such as L-theanine and antioxidants), leading to nutrient loss and degraded flavor.
Oxidation Risk: High-speed operation increases air exposure, accelerating oxidation. This darkens the matcha’s color (diminishing its vibrant green hue), weakens its flavor, and shortens its shelf life.
Inconsistent Particle Size: High-speed grinders struggle to achieve the fine, uniform consistency of traditional stone mills (ideal particle size: 5-10 micrometers). This results in coarse powder, affecting dissolvability and texture (potentially causing graininess or sedimentation).
Flavor Deterioration: Heat and oxidation may impart bitterness to matcha, masking its characteristic umami flavor and compromising overall flavor balance.
Equipment Dependency and Cost: Professional high-speed grinders are expensive, and low-quality equipment risks introducing metal contamination or impurities, affecting safety. Additionally, high-speed methods contradict the traditional slow-grinding process, diminishing the product’s cultural value.