Matcha Particle Size — Texture and Solubility
High-quality matcha achieves a particle size of 5–10 microns — fine enough to remain suspended in water as a colloidal dispersion for several minutes and produce a smooth mouthfeel without grittiness.
| Measure | Value | Unit | Notes |
|---|---|---|---|
| Target particle size: ceremonial grade | 5–10 | μm (microns) | Measured by laser diffraction (d50 value) |
| Culinary grade particle size | 10–20 | μm | Slightly coarser; acceptable for cooking, visible grittiness in thin applications |
| Suspension time at 5μm | 5–10 | minutes | Before significant settling occurs in still water; agitation (whisking) maintains suspension |
| Human sensory grit threshold | ~15–20 | μm | Particles above this size are perceptible as grit on the tongue |
| Stone mill RPM for 5–10μm target | 70–100 | RPM | Lower RPM produces finer particles but reduces throughput |
| Surface area increase vs. whole leaf | ~10,000× | Estimated; drives both solubility increase and oxidation acceleration |
Particle size is the physical property most directly responsible for matcha’s texture and drinking experience. The 5–10 micron target is not arbitrary — it represents the optimal balance between suspension stability, mouthfeel, and grinding practicality.
Why 5–10 Microns?
At 5–10 microns, matcha particles are:
- Small enough to form a colloidal suspension: They behave more like dissolved particles than suspended solids, staying distributed in water for minutes without settling
- Large enough to grind efficiently: Sub-5-micron grinding at stone mills becomes impractical due to particle agglomeration and heat generation
- Below the sensory grit threshold: Particles <15μm are imperceptible on the tongue; above 20μm, grittiness becomes noticeable
Laser Diffraction Measurement
Particle size in commercial matcha is measured by laser diffraction (also called laser particle size analysis). The instrument measures how laser light scatters off particles in suspension, calculating a particle size distribution. The d50 value — the median particle diameter — is the standard reported metric. High-quality matcha targets d50 ≤10μm; premium ceremonial matcha typically achieves d50 5–7μm.
How Particle Size Affects Drinking
A matcha with too-coarse particles (>20μm) will:
- Settle visibly within seconds of whisking
- Produce a gritty sensation on the palate
- Have a less intense green color per gram (less surface area for color expression)
- Form clumps more readily
A properly fine matcha stays suspended long enough to drink comfortably, produces a velvety mouthfeel, and has vibrant color intensity.
Surface Area and Oxidation
The grinding process that achieves 5–10μm particles also dramatically increases surface area — estimated at ~10,000× compared to whole tencha leaves. This surface area is why matcha oxidizes so much faster than whole-leaf tea and why proper airtight, dark, cold storage is critical after opening.