Why Stone-Ground Matcha Remains the Pinnacle of Quality

In ancient times, matcha was not purchased as a pre-milled powder. Instead, hosts would buy the processed tea leaves and grind them by hand using a traditional stone mill (Ishi-usu) right before welcoming their guests.

Today, true stone-ground matcha accounts for only about 20% of all matcha in circulation, with the remaining 80% produced by modern, high-speed pulverizing machines. While the stone mills of today are automated rather than turned by hand, this traditional method is still recognized as the marker of the absolute highest quality.

The secret lies in temperature and aroma. To unlock the rich, enchanting fragrance unique to stone-ground tea, the millstones must be perfectly warm. When the machines are turned off overnight, it takes up to five hours for the stone to warm up to the ideal temperature the next day. To overcome this, dedicated factories carefully schedule their automated stone mills to run continuously for 16 to 20 hours a day.

Even with modern automation, true stone-grinding remains an incredibly time-consuming and meticulous process. It makes you wonder—how drastically does it differ from high-speed machine powder? Tasting and comparing the two is an experience every matcha lover should try.