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ishizuchi kurocha two-stage fermentation

process / process-ishizuchi-kurocha-fermentation

石鎚黒茶の二段発酵

Ishizuchi kurocha two-stage fermentation is a two-stage fermentation in the production of (Ishizuchi-kurocha). After picking and heat-fixing, leaves undergo mold growth by filamentous fungi (aerobic fermentation, about 1 week), followed by anaerobic fermentation by lactic acid bacteria in a pickling stage (about 2 weeks).

On this page (7 sections)
  1. Overview
  2. Sources for this overview (2)
  3. Topic hubs
  4. Follow the connections
  5. Related entries (10)
  6. How processing and cooking change it (2)
  7. Safety and regulation (1)
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Reading the bitterness

「石鎚黒茶」 (Ishizuchi-kurocha) is produced mainly in July–August. After picking and heat-fixing, the leaves undergo mold growth by filamentous fungi (aerobic fermentation, about 1 week). They are then rolled and submerged in tubs or similar vessels for anaerobic fermentation by lactic acid bacteria (about 2 weeks), giving the process its distinctive two-stage fermentation. The tea is finished by sun-drying and selection.

This two-stage fermentation method was designated an Important Intangible Folk Cultural Property, 『石鎚黒茶の製造技術』 (in translation: "Manufacturing technique of Ishizuchi-kurocha"), on March 22, 2023. The area of transmission is the Ishizuchi district of Komatsu, Saijo, Ehime Prefecture, and the safeguarding organization is the Ishizuchi Kurocha Manufacturing Technique Preservation Society.

In a peer-reviewed paper using the same green tea as a control, the caffeine concentration in hot-water extracts of Ishizuchi-kurocha after two-stage fermentation was 13.9–15.7 mg/100 mL for 2 samples from different producers, compared with 43.7 mg/100 mL for green tea; total catechin concentration was 20.1–25.3 mg/100 mL, compared with 87.8 mg/100 mL for green tea. Among the 4 post-fermented teas compared in the same paper, Ishizuchi-kurocha retained the highest catechin concentration, particularly EGC.

Sources for this overview

  1. 石鎚黒茶の製造技術

    文化庁 / / government document / full text checked

    Checked for this overview: Confirmed the two-stage fermentation, comprising about 1 week of aerobic mold growth and about 2 weeks of submerged anaerobic fermentation, and the sequence of steps from picking through selection. / Confirmed the designation name and date, area of transmission, and safeguarding organization against the original Agency for Cultural Affairs record.

  2. Comparison of antioxidant activities among four kinds of Japanese traditional fermented tea

    Horie M; Nara K; Sugino S; Umeno A; Yoshida Y / 2017 / journal article / full text checked

    Checked for this overview: The comparison of caffeine and catechin concentrations with the green-tea control and the position as highest among 4 types.

Follow the connections

ishizuchi kurocha two-stage fermentation →reduces→ tea catechins →are main contributors to→ astringency

Structured claims — open a section to read each claim's confidence, evidence and limits

How processing and cooking change it (2)

ishizuchi kurocha two-stage fermentation is prepared by: Made through the processes of plucking, kill-green (fixation), mold inoculation (aerobic fermentation by filamentous fungi, about 1 week), rolling, pickling (anaerobic fermentation by lactic acid bacteria, about 2 weeks), sun-drying, and sorting. Mainly produced in July and August.supported

Scope: the Ishizuchi district of Komatsu, Saijo, Ehime Prefecture

Note: As recorded on Saijo City's official website.

Records: 『おもに７、８月の期間に製造され、摘採、殺青、カビ付け、揉捻、漬け込み、乾燥、選別の各工程がある。発酵に適した冷涼な山中の建物に茶葉を運び込み、二段階に分けて自然発酵させる』 (in translation: "Mainly produced during July and August, going through the processes of plucking, kill-green, mold inoculation, rolling, pickling, drying, and sorting. The tea leaves are carried into a cool mountain building suited to fermentation, and are naturally fermented in two stages.")
Limitations: No identification of the fungal species is given.
Source: 石鎚黒茶の製造技術 (文化庁) · full text checked
Show dataprocess-ishizuchi-kurocha-fermentation —is_prepared_by→ "Made through the processes of plucking, kill-green (fixation), mold inoculation (aerobic fermentation by filamentous fungi, about 1 week), rolling, pickling (anaerobic fermentation by lactic acid bacteria, about 2 weeks), sun-drying, and sorting. Mainly produced in July and August."
claim: clm-ishizuchikurocha-two-stage-process / type: processing / updated: 2026-09-01
ishizuchi kurocha two-stage fermentation reduces tea catechinssupported

Scope: Layer: Food. Green tea (unfermented, control) and Ishizuchi-kurocha (2 samples from different producers) extracted under identical conditions (hot water 100 mL, 1.5 g leaf, 5 minutes), n=5 comparison.

Table 1: Ishizuchi-kurocha 1: caffeine 13.9b, EGC 16.0b, EGCg 2.0b, EC 1.9b, GCg 0.1a, ECg 0.1b, total catechin 20.1b. Ishizuchi-kurocha 2: caffeine 15.7b, EGC 19.5b, EGCg 1.0b, EC 4.8ab, GCg 0.1a, ECg trace, total catechin 25.3b. Main text: "Among the postfermented teas, the concentration of all catechins was the highest in Ishizuchi-kurocha. In particular, the concentration of EGC in Ishizuchi-kurocha was high."
Limitations: Authors note small 2-producer differences, but the comparison uses separate green tea lots (control) rather than a single lot's before–after fermentation.
Source: Comparison of antioxidant activities among four kinds of Japanese traditional fermented tea (Horie M; Nara K; Sugino S; Umeno A; Yoshida Y, 2017) · full text checked
Show dataprocess-ishizuchi-kurocha-fermentation —reduces→ compound-catechins
claim: clm-w71c2-ishizuchikurocha-caffeine-catechin-reduced-vs-greentea / type: processing / updated: 2026-09-07

Safety and regulation (1)

ishizuchi kurocha two-stage fermentation is registered as Designated as an Important Intangible Folk Cultural Property under the name 『石鎚黒茶の製造技術』 (in translation: "Manufacturing technique of Ishizuchi-kurocha") on March 22, 2023. The area of transmission is the Ishizuchi district of Komatsu, Saijo, Ehime Prefecture. The preserving body is the Ishizuchi Kurocha Manufacturing Technique Preservation Society.contextual

Scope: Saijo, Ehime Prefecture

Note: Included after directly checking the original record in the Agency for Cultural Affairs' 「文化遺産オンライン」 (in translation: "Cultural Heritage Online") (heritage id 589236).

Records the designated name, designation category, date of designation, area of transmission, and preserving body.
Limitations: None (a direct confirmation of an institutional/administrative fact).
Source: 石鎚黒茶の製造技術 (文化庁) · full text checked
Show dataprocess-ishizuchi-kurocha-fermentation —is_registered_as→ "Designated as an Important Intangible Folk Cultural Property under the name 『石鎚黒茶の製造技術』 (in translation: "Manufacturing technique of Ishizuchi-kurocha") on March 22, 2023. The area of transmission is the Ishizuchi district of Komatsu, Saijo, Ehime Prefecture. The preserving body is the Ishizuchi Kurocha Manufacturing Technique Preservation Society."
claim: clm-ishizuchikurocha-registered-icfp / type: regulatory / updated: 2026-09-01

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