GOISHICHA
JAPANESE FERMENTED TEA
DARK (FERMENTED) TEA
★ PESTICIDE-FREE GARDENING
Ōtoyo, Kōchi, Shikoku, Japan
Goishicha is a rare Japanese post-fermented tea from Kōchi Prefecture, produced using a traditional two-stage fermentation method preserved by only a small number of artisans. The tea undergoes both aerobic and anaerobic fermentation, creating a highly distinctive profile unlike most other Japanese teas. The infusion is deep and unusual, offering sour-sweet fermentation notes, woody nuances, and a smooth, refreshing finish. MORE
AROMA
Spicy, seaweed
TASTE
Sweet and sour
CULTIVAR: Yamacha (Mountain Tea)
HARVEST: 2022
DARK (FERMENTED) TEA
★ PESTICIDE-FREE GARDENING
Ōtoyo, Kōchi, Shikoku, Japan
Goishicha is a rare Japanese post-fermented tea from Kōchi Prefecture, produced using a traditional two-stage fermentation method preserved by only a small number of artisans. The tea undergoes both aerobic and anaerobic fermentation, creating a highly distinctive profile unlike most other Japanese teas. The infusion is deep and unusual, offering sour-sweet fermentation notes, woody nuances, and a smooth, refreshing finish. MORE
AROMA
Spicy, seaweed
TASTE
Sweet and sour
CULTIVAR: Yamacha (Mountain Tea)
HARVEST: 2022
KUROCHA is one of the rarest and most unusual fermented tea styles in the world, produced through a unique two-stage fermentation process that combines aerobic and anaerobic microbial activity. As a result of this complex transformation, the tea develops a rich composition of organic acids, polyphenols, amino acids, minerals, and fermentation-derived compounds that contribute to both its distinctive flavor profile and traditionally valued properties.
The fermentation process dramatically alters the chemical composition of the tea leaves, creating a beverage characterized by deep umami, refreshing acidity, and remarkable complexity. It is believed that regular consumption of Kurocha may support digestive health, contribute to the balance of beneficial intestinal microflora, assist the body's natural antioxidant defenses, and promote healthy metabolism. Traditionally, this tea has also been appreciated for its refreshing yet grounding character, its ability to aid digestion after meals, reduce feelings of fatigue, and create a balanced state of mental clarity and physical well-being.
The fermentation process dramatically alters the chemical composition of the tea leaves, creating a beverage characterized by deep umami, refreshing acidity, and remarkable complexity. It is believed that regular consumption of Kurocha may support digestive health, contribute to the balance of beneficial intestinal microflora, assist the body's natural antioxidant defenses, and promote healthy metabolism. Traditionally, this tea has also been appreciated for its refreshing yet grounding character, its ability to aid digestion after meals, reduce feelings of fatigue, and create a balanced state of mental clarity and physical well-being.
Learn more about the BIOCHEMISTRY OF A TEA LEAF
SEED-GROWN TEA PLANT
This tea refers to a Qunzi Zhong, a "seed-grown tea plant". Unlike cloned or asexually propagated cultivars, which are created by cuttings or grafting from a single "mother" plant, Qunzi Zhong tea trees are grown from seeds. This results in a genetically diverse population of plants. Each seed-grown tea tree is unique, with slightly different characteristics. This genetic variety helps improve the resilience of the tea garden, making it more resistant to pests, diseases, and environmental stress. Seed-grown trees usually develop stronger and deeper roots than cloned plants, allowing them to draw nutrients and minerals from deeper soil layers, often giving the tea a more complex and rich flavor profile. Qunzi Zhong represents the traditional way of tea cultivation. Because of the genetic diversity, teas made from Qunzi Zhong plants tend to offer more layered and nuanced flavors, reflecting a richer expression of the local terroir (soil, climate, and environment).
PESTICIDE-FREE GARDENING
Pesticide-free gardening refers to a cultivation method in which no synthetic chemical pesticides are used at any stage of plant growth. Instead, this approach relies on biodiversity, ecological balance, and cultural practices to manage pests and diseases. Unlike conventional farming, which often depends on chemical intervention to control infestations, pesticide-free gardening emphasizes prevention through healthy soil, companion planting, and natural predators. This method fosters a more resilient and adaptive garden ecosystem. Without chemical inputs, beneficial insects such as ladybugs, lacewings, and native bees thrive, contributing to pollination and pest control. Untouched by harsh agents, the soil remains alive with microbial activity, supporting deeper root systems and more vigorous plant development. Over time, this results in produce with purer, more expressive flavors, reflecting the health of the environment and the grower's intention.
Learn more about Pesticide-Free Gardening
EASTERN (SENCHA DO) ★
Temperature: 99 °C
Amount: 5 grams per 150-200 ml of water
Steeping: 10-30 sec x 5
WESTERN (INFUSION)
Temperature: 99 °C
Amount: 5 grams per 1000 ml of water
Steeping: 15 min
Learn more about TEA BREWING METHODS
Tea absorbs surrounding aromas and moisture. This type of tea oxidizes when it comes into contact with oxygen and loses its properties, including taste and aroma. Store it in a dry and cool place in airtight packaging. Avoid direct exposure to the sun and high temperatures.
BEST BEFORE: 2 years since production date!
*Suitable for long-term aging. Under proper storage conditions, the tea may gradually develop increased depth, smoothness, and complexity.
BEST BEFORE: 2 years since production date!
*Suitable for long-term aging. Under proper storage conditions, the tea may gradually develop increased depth, smoothness, and complexity.
Learn more ABOUT TEA STORAGE
ABOUT
Goishicha is one of the rarest traditional fermented teas of Japan, produced in remote mountain areas of Kōchi Prefecture on the island of Shikoku. Historically, this tea was created as a method of preserving tea leaves through natural fermentation, developing a unique style entirely separate from the more familiar green tea traditions of Japan. Today, only a very small number of producers continue to preserve this labor-intensive and historically important craft.
The tea is especially known for its rare double fermentation process involving both aerobic and anaerobic stages. After steaming, the leaves first undergo surface fermentation exposed to air, and are later tightly compressed and fermented anaerobically, creating the tea’s distinctive sour-sweet and deeply fermented profile. Once fermentation is complete, the tea is cut into small square pieces resembling stones used in the traditional Japanese board game Go, which gave the tea its name.
Goishicha represents a unique intersection of tea, fermentation culture, and traditional food preservation techniques. Unlike most Japanese teas focused on freshness and green aromatic expression, Goishicha develops complexity through microbial transformation and maturation. The result is a highly distinctive tea appreciated for its unusual character, digestive qualities, and deep cultural significance within Japan’s traditional fermented tea heritage.
PRODUCTION
The production of Goishicha follows one of the most unusual and traditional fermentation methods found in Japanese tea culture. Freshly harvested tea leaves are first steamed to soften the material and prepare it for microbial transformation. After steaming, the leaves undergo an initial aerobic fermentation stage, during which naturally occurring microorganisms begin developing the tea’s characteristic fermented profile.
Following the first fermentation, the leaves are tightly packed, compressed, and sealed for a second anaerobic fermentation stage. During this process, lactic acid fermentation gradually develops, creating the tea’s distinctive sour-sweet character, soft texture, and deep aromatic complexity. The controlled interaction between oxygen-rich and oxygen-free fermentation stages is what makes Goishicha fundamentally different from most other fermented teas.
Once fermentation is complete, the compressed tea is cut into small square blocks resembling stones used in the traditional Japanese board game Go, giving the tea its name. The tea is then carefully dried and stabilized before storage. This rare double fermentation process requires significant experience and environmental sensitivity, making Goishicha one of the most technically and culturally unique teas of Japan.
Yamacha (“mountain tea”) refers to tea plants growing in the wild or semi-wild conditions across Japan, often on mountain slopes, forest edges, or abandoned tea fields. These plants are generally seed-grown and genetically diverse, not cloned cultivars. In many cases, yamacha overlaps with the horticultural term zairai, meaning “native variety” in the sense of locally adapted, seed-propagated tea. Although tea is not native to Japan, having been introduced from China centuries ago, seed-propagated plants escaped cultivation and adapted to local environments over generations. These wild-growing stands can be centuries old, showing wide variation in leaf size, flavor, and harvest timing. Historically, yamacha played an important role in rural tea culture, especially in regions where industrial cultivation never fully replaced local, naturalized bushes. Today, it remains valued for its resilience, distinct flavors, and connection to traditional Japanese tea-making methods. Goishicha is one of those unique teas in Japan, traditionally made from yamacha leaves and branches.
Check out our big article about visiting Goishicha production during our Japanese tea expedition 2025.
TERROIR
Goishicha originates from remote mountain areas of Kōchi Prefecture on the island of Shikoku, Japan. The region is characterized by steep mountainous terrain, dense forests, abundant rainfall, and a humid subtropical climate influenced by nearby river systems and mountain mist. These environmental conditions create a highly active microbial environment, which plays an important role in the tea’s traditional fermentation process.
Tea gardens are typically located in isolated mountain villages where cultivation remains small-scale and closely connected to local traditions. The combination of clean mountain air, mineral-rich soils, stable humidity, and natural biodiversity contributes to the tea’s distinctive depth and fermentation potential. The local climate supports both the growth of suitable tea material and the delicate balance required during microbial transformation.
The terroir of Kōchi emphasizes freshness, natural fermentation character, and atmospheric depth. Unlike many Japanese teas focused primarily on bright green freshness, the environment here supports the development of microbial complexity and layered sour-sweet fermentation notes. This combination of mountainous terroir and traditional fermentation culture gives Goishicha its highly distinctive identity within the world of Japanese tea.
ORGANOLEPTICS
The dry leaf appearance is dark and compressed into small square pieces, with deep brown and olive tones reflecting the tea’s double fermentation process. The aroma of the dry tea is highly unusual and expressive, combining notes of sour fruit, fermented grain, humid wood, dried herbs, and subtle lactic nuances. In a preheated teapot, the tea gradually opens, and the aroma becomes deeper and more atmospheric, revealing fermented plum, forest earth, warm grain, dried fruit, and soft woody sweetness. After a brief rinse, the leaves fully awaken, and the aroma gains remarkable integration, where sour-sweet fermentation tones, earthy warmth, and herbal freshness merge harmoniously.
The aroma of the liquor in the empty cup is rich and long-lasting, with pronounced fermented fruit and warm woody notes. The taste is smooth and deeply layered, with a rounded medium body and a soft, slightly creamy texture created through lactic fermentation. From the first sips, notes of fermented plum, dried apricot, humid wood, warm grain, and soft earthy sweetness emerge, balanced by refreshing acidity and almost no bitterness. The profile remains highly stable across multiple infusions, gradually revealing deeper mineral and herbal nuances. The aftertaste is long, refreshing, and slightly cooling, leaving lingering sour-sweet fruit notes and soft woody-mineral sensations in the throat. In the empty cup after drinking, rich aromas of fermented fruit, dried herbs, warm grain, and forest wood remain for a long time.
Goishicha is one of the rarest traditional fermented teas of Japan, produced in remote mountain areas of Kōchi Prefecture on the island of Shikoku. Historically, this tea was created as a method of preserving tea leaves through natural fermentation, developing a unique style entirely separate from the more familiar green tea traditions of Japan. Today, only a very small number of producers continue to preserve this labor-intensive and historically important craft.
The tea is especially known for its rare double fermentation process involving both aerobic and anaerobic stages. After steaming, the leaves first undergo surface fermentation exposed to air, and are later tightly compressed and fermented anaerobically, creating the tea’s distinctive sour-sweet and deeply fermented profile. Once fermentation is complete, the tea is cut into small square pieces resembling stones used in the traditional Japanese board game Go, which gave the tea its name.
Goishicha represents a unique intersection of tea, fermentation culture, and traditional food preservation techniques. Unlike most Japanese teas focused on freshness and green aromatic expression, Goishicha develops complexity through microbial transformation and maturation. The result is a highly distinctive tea appreciated for its unusual character, digestive qualities, and deep cultural significance within Japan’s traditional fermented tea heritage.
PRODUCTION
The production of Goishicha follows one of the most unusual and traditional fermentation methods found in Japanese tea culture. Freshly harvested tea leaves are first steamed to soften the material and prepare it for microbial transformation. After steaming, the leaves undergo an initial aerobic fermentation stage, during which naturally occurring microorganisms begin developing the tea’s characteristic fermented profile.
Following the first fermentation, the leaves are tightly packed, compressed, and sealed for a second anaerobic fermentation stage. During this process, lactic acid fermentation gradually develops, creating the tea’s distinctive sour-sweet character, soft texture, and deep aromatic complexity. The controlled interaction between oxygen-rich and oxygen-free fermentation stages is what makes Goishicha fundamentally different from most other fermented teas.
Once fermentation is complete, the compressed tea is cut into small square blocks resembling stones used in the traditional Japanese board game Go, giving the tea its name. The tea is then carefully dried and stabilized before storage. This rare double fermentation process requires significant experience and environmental sensitivity, making Goishicha one of the most technically and culturally unique teas of Japan.
Yamacha (“mountain tea”) refers to tea plants growing in the wild or semi-wild conditions across Japan, often on mountain slopes, forest edges, or abandoned tea fields. These plants are generally seed-grown and genetically diverse, not cloned cultivars. In many cases, yamacha overlaps with the horticultural term zairai, meaning “native variety” in the sense of locally adapted, seed-propagated tea. Although tea is not native to Japan, having been introduced from China centuries ago, seed-propagated plants escaped cultivation and adapted to local environments over generations. These wild-growing stands can be centuries old, showing wide variation in leaf size, flavor, and harvest timing. Historically, yamacha played an important role in rural tea culture, especially in regions where industrial cultivation never fully replaced local, naturalized bushes. Today, it remains valued for its resilience, distinct flavors, and connection to traditional Japanese tea-making methods. Goishicha is one of those unique teas in Japan, traditionally made from yamacha leaves and branches.
Check out our big article about visiting Goishicha production during our Japanese tea expedition 2025.
TERROIR
Goishicha originates from remote mountain areas of Kōchi Prefecture on the island of Shikoku, Japan. The region is characterized by steep mountainous terrain, dense forests, abundant rainfall, and a humid subtropical climate influenced by nearby river systems and mountain mist. These environmental conditions create a highly active microbial environment, which plays an important role in the tea’s traditional fermentation process.
Tea gardens are typically located in isolated mountain villages where cultivation remains small-scale and closely connected to local traditions. The combination of clean mountain air, mineral-rich soils, stable humidity, and natural biodiversity contributes to the tea’s distinctive depth and fermentation potential. The local climate supports both the growth of suitable tea material and the delicate balance required during microbial transformation.
The terroir of Kōchi emphasizes freshness, natural fermentation character, and atmospheric depth. Unlike many Japanese teas focused primarily on bright green freshness, the environment here supports the development of microbial complexity and layered sour-sweet fermentation notes. This combination of mountainous terroir and traditional fermentation culture gives Goishicha its highly distinctive identity within the world of Japanese tea.
ORGANOLEPTICS
The dry leaf appearance is dark and compressed into small square pieces, with deep brown and olive tones reflecting the tea’s double fermentation process. The aroma of the dry tea is highly unusual and expressive, combining notes of sour fruit, fermented grain, humid wood, dried herbs, and subtle lactic nuances. In a preheated teapot, the tea gradually opens, and the aroma becomes deeper and more atmospheric, revealing fermented plum, forest earth, warm grain, dried fruit, and soft woody sweetness. After a brief rinse, the leaves fully awaken, and the aroma gains remarkable integration, where sour-sweet fermentation tones, earthy warmth, and herbal freshness merge harmoniously.
The aroma of the liquor in the empty cup is rich and long-lasting, with pronounced fermented fruit and warm woody notes. The taste is smooth and deeply layered, with a rounded medium body and a soft, slightly creamy texture created through lactic fermentation. From the first sips, notes of fermented plum, dried apricot, humid wood, warm grain, and soft earthy sweetness emerge, balanced by refreshing acidity and almost no bitterness. The profile remains highly stable across multiple infusions, gradually revealing deeper mineral and herbal nuances. The aftertaste is long, refreshing, and slightly cooling, leaving lingering sour-sweet fruit notes and soft woody-mineral sensations in the throat. In the empty cup after drinking, rich aromas of fermented fruit, dried herbs, warm grain, and forest wood remain for a long time.
HEI CHA (DARK TEA)
Explore more Hei Cha (Dark Tea) from the AN SHIM TEA Collection.