Jukusei: the quiet aging process behind great matcha
Often when we speak about matcha, the harvest takes centre stage: the shaded tea gardens, the first spring leaves, the careful steaming and drying of tencha. But some of the most important work happens after the harvest.
This stage is called jukusei (熟成): is the aging process known as maturation.
Jukusei is the controlled resting period where finished tencha, the leaf material which is later stone-milled into matcha, is stored before milling. Rather than grinding immediately after the spring harvest, many producers allow the tencha to settle for several months in carefully managed, low-temperature storage. The aim is to let the tea flavours to become more developed.
Tencha first, matcha later
A useful distinction: it is the tencha that matures, not the finished matcha powder.
After harvesting, shaded leaves are steamed to stop oxidation, dried, and refined into tencha. This material is then stored until the producer decides it is ready to be milled. Only then does the tencha pass slowly through a stone mill and become matcha.
This is why freshly milled matcha matters. The long preparation happens before milling; once ground, its vivid aroma, colour, and delicate character are best enjoyed relatively soon.
Where and how tencha rests
After processing, tencha is packed away,. Temperature and humidity are closely controlled throughout. In many cases, tencha rests at around 0–5 degrees in a dry, low-humidity environment, shielded from oxygen and heat.
The autumn tea tradition
The practice of maturing tea is closely connected to the Japanese tea calendar.
Historically, tencha was sealed in tea jars after the spring harvest and stored through summer. In autumn, the jar would be opened in a ceremony known as kuchikiri, literally, "opening the mouth" of the jar. The tea would then be milled.
In Uji, this moment traditionally marks the beginning of the tea season. Around the first weeks of October and into early November, tea practitioners begin to enjoy tea that has rested since spring. The exact timing differs between tea schools, producers, but autumn has long been the season associated with opening stored tea.
Freshness, rethought
"Fresh" is an important word in matcha, but it needs context. Freshly milled matcha is desirable. At the same time, the tencha used to make it may have rested and matured for a considered period before it ever entered the mill.
Higashisonogi 2025
Wazuka 2024
