Hiroshima Zairai Koji Fermented Black Tea - Made with Sake Koji and Native Tea Leaves Craft Tea by TEA FACTORY GEN 20g/0.70 oz

Since its founding in 1972, TEA FACTORY GEN is a tea atelier based in the Sera Highlands of Hiroshima, Japan.
They honor nature and tradition, producing tea through a fully integrated process using no chemical fertilizers or pesticides.

Hiroshima native(zairai) tea

"Native tea" is tea planted and grown from seeds, and is a valuable tea that is said to account for only 3% of all tea in circulation.

Their native tea is 60 to 70 years old. The roots extend more than 2 meters deep into the ground, providing nutrients from the ground that are rich in minerals.

Additionally, because it is grown without fertilizers or pesticides, the tea may lack the concentrated umami typically prized in gyokuro.

However, it offers something even more essential: the natural sweetness of the leaf, a clean, refreshing flavor, and the untamed vitality of the land itself.

Rarity No.1: Hiroshima Indigenous Ko-ji Fermented Black Tea

They crafted this unique black tea by carefully picking leaves from long-standing tea trees in Sera Town, Sera District, Hiroshima Prefecture, and fermenting them with tane-koji—a fermentation starter traditionally used in sake brewing.

Black tea typically gains its flavor through oxidation. However, they had long felt a disconnect with calling this process “fermentation.” Motivated by a desire to create a tea that truly involves fermentation, they embarked on developing a new kind of tea using koji.

Koji is an ancient fermentation method that has been cherished in Japan for centuries. By utilizing Japan’s native koji mold, they succeeded in producing a completely original tea that can’t be found anywhere else in the world. Encountering the power of koji, which has an even longer history than tea itself, deeply moved them. The invisible collaboration between microorganisms and tea leaves brought forth a flavor unlike anything they had ever experienced.

This fermented black tea has a rich depth, reminiscent of sake or amazake, paired with a gentle, smooth mouthfeel. It's highly nutritious and especially recommended for those who value wellness and health.

By honoring the historical legacy of koji while aligning with modern tastes, they have created a tea that embodies both tradition and innovation. The natural aroma of the tea leaves and the mellow, umami-rich fragrance born from fermentation blend in perfect harmony. The result is a flavor that’s both distinctive and warmly inviting.

They invite you to experience this one-of-a-kind fermented black tea—something truly unique and unlike any tea you've had before.

Recommend way
How to Brew?

To maintain the proper temperature, pre-warm your teaware before brewing.
Use 2g of tea leaves per 100ml of boiling water. Steep in a teapot for 3 minutes.
For a second infusion, also use boiling water and steep for at least 3 minutes.