Tencha — The Leaf Form Before Grinding
Tencha is shade-grown tea leaf that is steamed, air-dried flat (not rolled), then de-stemmed and de-veined before stone-grinding into matcha. The flat drying and removal of stems and veins distinguish it from all other green tea forms.
| Measure | Value | Unit | Notes |
|---|---|---|---|
| Steaming duration (tencha) | 15–25 | seconds | Longer than sencha (10–15s) to fix enzymes and preserve color |
| Drying method | Air-dried flat in belt dryer | Not rolled — preserves leaf structure for efficient de-stemming | |
| Stem and vein removal (koicha standard) | ~90 | % removal | Stems and veins reduce grinding quality and add bitterness |
| Weight loss during tencha processing | ~80 | % | Water loss during drying; 1kg fresh leaf → ~200g tencha |
| Tencha storage temperature | −20 to −5 | °C | Frozen storage maintains quality for up to 12–18 months before grinding |
| Grinding loss rate | ~5 | % | Minimal; grinding is efficient but produces some unusable dust fraction |
Tencha (碾茶, literally “grinding tea”) is the intermediate form of shade-grown green tea before it becomes matcha. Understanding tencha is essential to understanding why matcha has the texture, color, and flavor it does — as each processing decision at the tencha stage directly shapes the final powder.
The Distinction from Sencha
Both sencha and tencha start as shade-grown or sun-grown Camellia sinensis leaves. But their processing diverges immediately after harvest:
- Sencha: Steamed, rolled repeatedly into needle-like shapes, dried. Rolling is critical — it shapes the leaf and drives the pan-drying that produces sencha’s characteristic flavor.
- Tencha: Steamed, dried in a continuous flat belt dryer, NOT rolled. The flat drying maintains the leaf’s natural shape and makes it easy to strip stems and veins in the next step.
Rolling would create leaf fragments too irregular for efficient de-stemming and would damage the cellular structure needed for smooth grinding.
De-Stemming and De-Veining
After drying, tencha passes through a cutter and an air-sorter system that separates the tender leaf blade from the tougher stem and vein tissue. This is called “aracha” refining. The removed stems and veins contain:
- Higher tannin content (more astringent)
- Lower amino acid concentration
- Different mineral composition
- Coarser texture that grinds less smoothly
High-quality ceremonial-grade matcha removes ~90% of stems and veins. Lower-grade matcha includes more stem material, which reduces quality and increases bitterness.
Storage Before Grinding
Tencha quality peaks immediately after production but can be preserved by frozen storage at −20°C to −5°C for up to 18 months. Many producers grind tencha in batches through the year, keeping larger lots frozen to ensure freshness. Once ground into matcha, oxidation accelerates significantly, which is why matcha has a shorter shelf life than tencha.