Matcha Processing Steps — Farm to Powder
Matcha production requires 7 steps: shading (20–30 days), hand harvest, steam fixation (15–25 seconds, 100°C steam), air cooling, belt drying, de-stemming/de-veining to produce tencha, and stone grinding at 30–40g/hour.
| Measure | Value | Unit | Notes |
|---|---|---|---|
| Step 1: Shade duration | 20–30 | days | Blocks 70–90% sunlight; accumulates L-theanine and chlorophyll |
| Step 3: Steam fixation temperature | 95–100 | °C | 100°C steam for 15–25 seconds inactivates oxidative enzymes |
| Step 3: Steam fixation time | 15–25 | seconds | Longer than sencha (10–15s) to ensure full enzyme inactivation |
| Step 5: Drying temperature | 80–120 | °C | Belt dryer; temperature managed to avoid flavor degradation |
| Step 6: Stem/vein removal efficiency | 80–95 | % | Higher removal = higher grade; mechanical air separation |
| Step 7: Grinding rate | 30–40 | g/hour | Granite millstone; slow to prevent heat-induced degradation |
Understanding matcha production requires following the leaf through each transformation from living plant to fine green powder. Each step is irreversible — a mistake at steaming or grinding cannot be corrected downstream.
The Seven Steps
1. Shading (Oishigake)
Beginning 20–30 days before harvest, shade structures are erected over the tea rows. Light reduction to 10–30% of ambient levels triggers the L-theanine accumulation and chlorophyll intensification that define matcha’s character.
2. Harvest (Tsunde)
First-flush leaves — the top one or two leaves and a bud — are harvested by hand (high grade) or machine (commercial grade). The harvest window is 10–15 days in April–May. Speed matters: leaves harvested even a few days late are measurably coarser and less amino-acid-rich.
3. Steam Fixation (Mushisei)
Fresh leaves contain oxidative enzymes (polyphenol oxidase) that would rapidly turn them brown, as in black tea processing. Steam fixation at 95–100°C for 15–25 seconds denatures these enzymes within seconds, “fixing” the green color and fresh flavor. This step distinguishes all Japanese green teas (steamed) from Chinese green teas (typically pan-fired).
4. Cooling and Leaf Straightening
After steaming, leaves pass through a cooling section where forced air removes surface moisture and cools the leaf to near-ambient temperature. This prevents carry-over cooking and prepares the leaf for uniform drying.
5. Drying (Belt Drying)
Unlike sencha, which is rolled during drying, tencha-destined leaves are dried flat on a moving belt conveyor. The belt passes through a drying tunnel at 80–120°C. Drying removes approximately 80% of the leaf’s original water content, taking fresh leaf from ~75% moisture to ~5% moisture.
6. De-Stemming and De-Veining (Koicha Finishing)
The dried flat leaves pass through cutting and air-separation equipment that removes stems and veins. Stems contain fewer amino acids and more tannins; their removal is essential for quality. The resulting product is tencha — the grinding-ready intermediate product.
7. Stone Grinding (Ishiusu)
Tencha passes through granite millstones at 30–40g/hour per millstone. Particle size is calibrated to 5–10 microns. After grinding, matcha is sifted, weighed, and sealed in nitrogen-flushed packaging to prevent oxidation.