Stone Mills in General
The Significance of Grinding with a Stone Mill and the Structure of the Stone Mill
A millstone from ancient times
A millstone is originally a simple tool designed to grind materials into powder
Since ancient times, millstones have been used to grind a wide variety of materials?rice, wheat, buckwheat, corn, salt, tea leaves, and more?which vary greatly in size and hardness.
Traditional millstones are generally large stones with deep grooves, designed to serve as a one-size-fits-all solution.
Naturally, when grinding different materials with the same millstone, people adjusted their grinding techniques accordingly.
For large or hard materials, the grinding is done slowly, adding the ingredients little by little.
For small or soft materials, a slightly larger amount can be added at once.
In both cases, the condition of the powder is closely observed during the process, and finally, the ground powder is sifted through a fine mesh to separate it.
Simply turning the millstone does not guarantee good powder; mastering the grinding technique requires skill and experience.
The millstone handcrafted by me
Traditional millstones were made with a diameter of around 30 centimeters and built heavy to grind hard materials into powder.
To ensure that millstone craftsmanship survives in modern life, I create specialized millstones for grinding coffee beans and for grinding tencha into matcha.
Because each is designed for a specific purpose, the size of the millstones has been reduced to the minimum necessary for effective use.
Moreover, the desired texture of the powder differs?coffee is ground to a medium grind, while matcha requires an ultra-fine grind.
As a result, the internal carving of each millstone has been specially designed to suit its intended purpose.
A useless matcha millstone I found in Kyoto
Matcha millstone
Turning Tencha into Matcha: The Art of Handcrafted Stone Mill Grinding
Grinding tencha into ultra-fine particles produces matcha.
While gyokuro is also a shade-grown tea, it undergoes a kneading process during finishing, resulting in rolled, stick-like leaves.
Additionally, tencha has its stems carefully removed, distinguishing it from gyokuro.
However, with careful grinding techniques, gyokuro can also be ground into matcha.
(For detailed methods, please refer to the "Turning Gyokuro into Matcha" page.)
Tencha, lacking the kneading process, remains flat and fragile, resembling crushed leaves.
Traditional matcha used in tea ceremonies is so finely ground that it feels smooth on the palate and froths beautifully.
My handcrafted matcha stone mills aim to replicate the perfect matcha produced by commercial electric stone mills that operate continuously for 24 hours, but in a compact, hand-cranked form.
To achieve this, my mills are designed larger and heavier compared to commonly available matcha mills.
The gap between the upper and lower stones is set to 1.5mm, and the grooves are carved to a depth of 0.5mm?extremely narrow and shallow.
This design limits the amount of tea leaves entering the mill, ensuring they are ground into ultra-fine powder.
When the tea leaves match the specified conditions, you can fill the upper stone's hole entirely and begin grinding, achieving perfect matcha.
If the grind is coarse, add small amounts of leaves at a time, turning the upper stone several times between additions to adjust the powder's fineness.
If grinding proves difficult, try gently crushing the leaves by hand before grinding.
Stone mills have a simple structure without adjustment features, making it challenging to accommodate various tea leaf varieties and finishing states.
Therefore, the user must adapt their technique accordingly.
Some customers have returned my handcrafted matcha mills, stating they couldn't achieve a proper grind, due to a lack of understanding of this aspect.
Replicating the results of a large commercial matcha mill in just a few minutes with a small hand mill naturally requires the user's ingenuity.
After a few trial runs, you'll grasp the relationship between grinding techniques and powder quality.
Subsequently, you'll be able to use the stone mill freely, producing everything from ceremonial-grade matcha to slightly coarser, vibrant green matcha suitable for cafe-style items?all with the same mill.
＜Another Important Feature of the Matcha Stone Mill＞
Both tencha and gyokuro are extremely high-grade and expensive tea leaves, so it's important to minimize any loss of leaves left inside the mill.
The image on the left shows the lower millstone after the upper stone has been removed during grinding. You can see unground tea leaves remaining only in the central area.
These central leaves can be collected and reused for the next session.
Virtually no leaves remain on the other surfaces.
The mill is designed to ensure that this precious tea is used as efficiently as possible, with minimal waste.
Coffee millstone
Grinding Coffee with a Stone Mill: A Unique Journey of Flavor and Aroma
Grinding coffee with a stone mill brings out a unique flavor and aroma that cannot be achieved by other means.
By slowly grinding the beans, almost no frictional heat is generated. In contrast, electric grinders operate at high speeds, producing heat that can slightly diminish the coffee’s natural aroma and flavor.
Stone mills, however, allow for low-temperature grinding, preserving the beans’ original character and richness.
Additionally, stone milling produces fewer ultra-fine particles (micro-powder). The consistently ground particles result in a smooth water flow during brewing, reducing bitterness and off-flavors.
This leads to a clearer taste and a mellow, rounded mouthfeel in your cup.
The coarseness of the grind can be easily adjusted by simply changing how the beans are added.
Although grinding with a stone mill takes time, the manual process itself has a relaxing effect.
Using traditional methods to grind beans creates a deeper appreciation and satisfaction, enhancing the overall coffee experience.
Coffee ground with a stone mill is known for its rich body and gentle aroma.
Lightly roasted beans especially highlight their fruity aroma and bright acidity, while dark roasts yield a more smoky and intense flavor profile.
Grinding coffee with a stone mill is more than just crushing beans?it's a thoughtful process that draws out the full individuality of the beans.
By grinding slowly and manually, both the taste and aroma are enriched, transforming your daily coffee into a more luxurious experience.
The mechanical design of a millstone
The stone mill is equipped with a handle for rotating the upper millstone.
While the system involves inserting a handle or wooden rod and turning it manually, my stone mill is designed with a precisely carved handle receiver, crafted from the same material as the upper millstone itself, ensuring stability and ease of rotation.
The upper millstone features a hole, which serves as the inlet for grains or beans.
The ground powder is discharged through a hole located on the outer side of the lower millstone. A tray is placed at the outlet to make it easier to collect the powder.
The structure of the stone mill is simple yet designed to grind materials uniformly. It plays a crucial role in bringing out the natural flavors of the ingredients.
