Stone tea mill
A pair of cut granite wheels that grind tencha into matcha. It is slow on purpose: the grooves cut into the stones shear the leaf rather than crushing it, and turning slowly keeps the powder cool, because heat during milling is what dulls the aroma of the finished tea.
Identity
- Category
- Accessory
- Native name
- 茶臼
- Romanised
- chausu, ishiusu
- Also called
- matcha stone mill, granite tea mill
- Material
- Cut granite, hand-cranked or motor-driven
- Skill level
- Advanced
Porous — this changes how it is used
Porous. It takes up a trace of every tea brewed in it and gives some of that back to the next, which is why such a vessel is kept for one tea rather than shared across a shelf.
Granite is a porous stone that holds aromatics, which is why a mill used for tea is used for nothing else. It is also why a mill should never be washed — water in the stone and residual powder in the grooves is how a mill sours.
Where it comes from
Japanese in its tea application, though the mechanism is a general stone quern used across the world for grain. The tea-specific part is the groove pattern and the slow turning speed.
Named here rather than presented as generic equipment. The object belongs to a practice, and TeaHQ describes it from the outside.
If you do not own one
Buying matcha already milled, which is what nearly everyone does. Throughput is the reason: a mill of this kind is commonly described as producing on the order of tens of grams in an hour, and a domestic spice grinder cannot substitute because it heats the leaf and produces a coarse powder that will not suspend.
This one is not marked essential. The tea can be made without it.
Brewing methods it is used for
- Whisking (bowl-prepared powdered tea) — Powdered leaf suspended in water rather than steeped and strained — the only common preparation in which the leaf itself is consumed rather than discarded.
- Koicha (thick matcha) — Matcha prepared thick enough to pour like paint rather than to whisk into foam. It is not a stronger version of everyday matcha but a separate preparation with its own motion, its own grade of powder and, in chanoyu, its own place in the sequence — and it is the older of the two.
Tea types it suits
Care and maintenance
Brush the grooves out dry; never wash the stones. Store the halves apart so air reaches both faces. Grind only tencha — dried destemmed shaded leaf — because stems and ordinary sencha leaf will not reduce to the required fineness.
Other accessorys
- Alcohol burner
- Cha dao utensil set
- Cha he (tea presentation vessel)
- Charcoal brazier (fenglu)
- Cup stand (chatuo)
- Electric ceramic tea stove
- Futaoki (lid and ladle rest)
- Hishaku (bamboo water ladle)
- Induction plate
- Kensui (waste water vessel)
- Kusenaoshi (whisk stand)
- Mortar and pestle
- Podstakannik (glass holder)
- Ro and furo (hearth and brazier)
- Ryoro (senchado charcoal stove)
- Tea boat
- Tea cloth
- Tea cosy
- Tea mat (chaxi cloth)
- Tea pet
- Tea pick (cha dao)
- Tea tongs
- Tea tray (cha pan)
- Teapot warmer
- Waste water bowl (jianshui)
- Water cooling bowl (sukwoo)
- Water filter jug
- Yuzamashi (water cooler)
Sources
This page is TeaHQ synthesis. No external source stands behind the description, the material or the account of how the object is cared for. Where the record names a tradition, that attribution is TeaHQ’s own reading of common practice rather than a citation.
In the chronology
- The technique matures across the Edo period and is mechanised in the twentieth century — Tencha, the stone mill, and why matcha is expensive
TeaHQ names no maker, brand or shop and has nothing to sell. Nothing on this page should be read as advice to buy the object — the substitute note above exists because owning it is usually optional.