What is Tencha?
The second big difference is how the tea leaf is processed after harvest. In fact, and this is BIG, matcha isn’t matcha until it is milled from tencha.
Freshness is one of the most important factors in Japanese tea, especially matcha, so the whole leaves are placed in cold storage refrigeration until they are ready for milling, which is when an order is placed. The HIGHEST QUALITY matcha is milled to order, placed in a small canister flushed with nitrogen to remove any trace of deteriorating oxygen, then sealed with a lid engineered with a rubber gasket to make it airtight. This particular detail ensures the matcha stays as fresh as possible after opening.
In Japan, two of the top tea classifications are cultivated in the exact same way with shading methods and timings: gyokuro and matcha. After the leaves are hand picked, they take two distinctly separate routes: one becomes tencha which gets milled into matcha, and one goes the other way to become gyokuro, the top steeped tea. You may have been misled into thinking that matcha is milled gyokuro. It’s NOT. Matcha is milled tencha. This confusion comes mainly because the leaves which become gyokuro are grown in almost the same way and quite often in the same location as the leaves used to make matcha.
Milling Tencha into Matcha Tea Powder
In order to understand matcha, we first need to get to grips with high grade, shade-grown tencha and gyokuro. While gyokuro uses the finest, most delicate leaves for steeping, tencha uses the best but slightly larger leaves, which could be shaded even longer depending on a host of factors.
The larger leaves are more fibrous which is vital for proper micro-milling into matcha. Think kale v baby leaf lettuce. Some tencha could even be shaded for up to 8 weeks, though this is quite rare. This extra shading also makes the green color much more intense. For matcha to achieve a luxuriously talc-like consistency, the fibrous stems and veins must be removed before milling. It requires fairly robust, flat leaves for milling so there is no rolling in the production process.
The leaves become tencha only after the stems and veins have been removed. The stems are then reserved for high-grade kukicha called shiraore or karigane (see video explanation here). Tencha is more like confetti with flat, broken up, smaller pieces of leaves. Tencha can be steeped but most of it is milled into matcha.
Using a stone mill, usually made of granite, tencha is ground into a micro-powder so fine that it feels like talcum powder and the particle size is finer than the smoke of a cigarette. Particle size does vary, with lower grades having larger particles. On average a mill can only produce about one to two ounces, roughly 30 to 50 grams per two hours. We are talking about 2 to 3 tablespoons per hour!