Raw material / 原材料Beverage ingredients

Goishi-Cha (Post-Fermented Tea)

碁石茶 (Goishi-cha)

Why source from Japan

Goishi-cha is one of only ~3 post-fermented Japanese teas; Otoyo cooperative has held the production protocol for 400+ years; Japan-domestic intangible cultural heritage.

Key spec

Caffeine very low (0.5-1.5%); polyphenol 8-15%; characteristic lactic-acid bacteria (Lactobacillus plantarum) fermentation profile.

Typical end-product

Boutique tea retail, fermented-tea collector market, traditional-craft amenity sets.

At a glance

Suppliers listed: Phase 1 onboarding in progress
Typical MOQ: 1–10 kg compressed cubes; 100 g – 1 kg loose product
Typical lead time: 12–20 weeks (cooperative allocation-controlled)
Regions of origin: Kochi (Otoyo)
Category: Beverage ingredients
Harvest season: Tea leaf July – August; fermentation 2-month cycles
Japan regulatory status: Food product; specific Otoyo cooperative production; intangible cultural heritage status
Japanese name: 碁石茶
Romaji: Goishi-cha

About this ingredient

Rare double-fermented post-fermented tea produced exclusively in Otoyo, Kochi Prefecture. Distinguished by its black-stone-like compressed cubes (the 'goishi' name references Go board stones), goishi-cha is one of only a handful of post-fermented teas in the world (alongside Chinese pu-erh and Japan's awa-bancha and ishizuchi-kurocha). Production is controlled by a small Otoyo cooperative — annual output is limited to less than 10 tonnes. Functional positioning targets the lactic-acid bacteria fermentation profile and resulting low-caffeine / high-polyphenol balance. Niche but increasingly sought by tea collectors and natural-fermentation enthusiasts in export markets.

Regulatory status

Japan	Food product; specific Otoyo cooperative production; intangible cultural heritage status
EU	Food import; CN 0902 (tea) classification
United States	GRAS by traditional tea use; FDA Prior Notice required
China	GACC food facility registration

Looking for alternatives?

Common reasons buyers swap to a different ingredient — and what we'd suggest based on this ingredient's profile.

Vegan / plant-based alternatives

Goishi-Cha (Post-Fermented Tea) is animal-derived. If you need a non-animal source with similar functions, consider:

Easier China regulatory path

Goishi-Cha (Post-Fermented Tea) faces a more restrictive regulatory pathway in China. These alternatives have a simpler status in that market:

When does it make sense to swap an ingredient? Read the swap guide →

Japanese suppliers

Phase 1 manufacturer onboarding is in progress. If you are actively sourcing this ingredient and would like to be introduced to candidate Japanese producers, send an inquiry and our team will return with options.

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Last updated: 2026-05-05

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