SE-12 : Tea

ICO Std 2002 — Extension SE-12

This extension module specifies the requirements and methodologies for ranking and evaluating tea and tea-related products. Tea rankings present distinctive methodological challenges: the vast diversity of tea types (six primary categories plus re-processed teas and herbal infusions) requires highly differentiated indicator systems; terroir and cultivar identity are paramount yet difficult to verify objectively; the integration of centuries-old artisanal craftsmanship with modern quality assurance demands balanced evaluation frameworks; and the critical importance of pesticide residue and food safety compliance in tea necessitates rigorous testing protocols. This module extends the core-layer methodology (Chapters 4 through 10) by defining domain-specific indicators, data collection protocols, safety assurance mechanisms, and scoring procedures for tea evaluation. It is applicable to rankings across all categories of tea, from primary tea types through re-processed teas to herbal infusions.

SE-12.1 Scope and Applicable Objects

SE-12.1.1 Scope

This module applies to the design, execution, and publication of rankings that evaluate tea and tea-related products. It covers:

a) the six primary tea categories, classified by processing method and oxidation level:

1) Green tea (绿茶): unoxidised teas produced by heat treatment (kill-green/杀青) to inactivate polyphenol oxidase. Sub-categories by kill-green method:

2) Black tea (红茶): fully oxidised teas (ref: GB/T 13738 series):

3) Oolong tea (乌龙茶/青茶): partially oxidised teas (ref: GB/T 30357 series):

4) White tea (白茶): minimally processed teas produced by natural withering and drying (ref: GB/T 22291):

5) Yellow tea (黄茶): lightly oxidised teas with a characteristic men huang/闷黄 (sealed yellowing) process (ref: GB/T 21726):

6) Dark tea (黑茶): post-fermented teas:

b) re-processed tea categories:

1) Scented tea (花茶): tea base blended or layered with flowers (ref: GB/T 22292 for jasmine tea; GB/T 34779 for scented tea processing):

2) Compressed tea (紧压茶): tea pressed into cakes, bricks, tuo shapes, or other forms (ref: GB/T 9833 series):

3) Extract tea (萃取茶): instant tea, tea concentrates, and liquid tea extracts (ref: ISO 7516);

4) Blended/compound tea (调制茶): teas blended with other ingredients (ref: GH/T 1247);

5) Tea bags (袋泡茶): tea packaged in filter material sachets;

6) Artistic/craft tea (工艺茶): decorative tea products formed into artistic shapes;

c) herbal infusions (代用茶): non-Camellia sinensis plant materials used for infusion, including:

SE-12.1.2 Applicable Objects

This module shall apply to rankings of:

a) individual tea products within a defined category or appellation;

b) tea product lines from a single producer, garden, or factory;

c) tea brands evaluated on aggregate quality metrics, including origin and craftsmanship indicators.

SE-12.1.3 Exclusions

This module does not apply to:

a) tea-flavoured beverages, ready-to-drink (RTD) tea products, which are covered under SE-01 (Consumer Products);

b) tea-derived pharmaceutical or nutraceutical products subject to separate regulatory frameworks;

c) tea supplements in capsule or tablet form not intended as traditional tea infusion.

SE-12.2 Normative References

The following referenced documents are indispensable for the application of this module.

a) ISO 17025:2017 — General requirements for the competence of testing and calibration laboratories;

b) ISO 3720:2011 — Black tea — Definition and basic requirements;

c) ISO 7516:2011 — Instant tea — Specification;

d) ISO 11287:2011 — Green tea — Definition and basic requirements;

e) GB/T 14456 series — Green tea (绿茶);

f) GB/T 13738 series — Black tea (红茶): Part 1 Broken black tea, Part 2 Congou black tea, Part 3 Souchong black tea;

g) GB/T 30357 series — Oolong tea (乌龙茶): Part 1 Basic requirements, Part 2 Tieguanyin, Part 3 Huangjin Gui, Part 4 Shui Xian, Part 5 Rou Gui, Part 6 Dancong, Part 7 Foshou, Part 8 Da Hong Pao;

h) GB/T 22291 — White tea (白茶);

i) GB/T 21726 — Yellow tea (黄茶);

j) GB/T 32719 series — Dark tea (黑茶): Part 1 Basic requirements, Part 2 Huajuan tea, Part 3 Xiangjian tea, Part 4 Liu Bao tea, Part 5 Fu tea;

k) GB/T 22111 — Geographic indication product — Pu’er tea (地理标志产品 普洱茶);

l) GB/T 18650 — Geographic indication product — Longjing tea (地理标志产品 龙井茶);

m) GB/T 9833 series — Compressed tea (紧压茶);

n) GB/T 22292 — Jasmine tea (茉莉花茶);

o) GB/T 34779 — Scented tea processing technical specification (花茶加工技术规范);

p) GH/T 1247 — Flavoured tea (调味茶);

q) GB 31608 — National food safety standard — Tea leaves (食品安全国家标准 茶叶);

r) GB 2762 — National food safety standard — Maximum levels of contaminants in foods (食品安全国家标准 食品中污染物限量);

s) GB 2763 — National food safety standard — Maximum residue limits for pesticides in foods (食品安全国家标准 食品中农药最大残留限量);

t) GB/T 23776 — Tea sensory evaluation methodology (茶叶感官审评方法);

u) GB/T 8302 — Tea — Sampling (茶叶 取样);

v) GB/T 8305 — Tea — Determination of water extract (茶叶 水浸出物测定);

w) GB/T 8313 — Determination of tea polyphenols and catechins in tea (茶叶中茶多酚和儿茶素类含量的检测方法);

x) GB/T 30375 — Tea storage (茶叶贮存);

y) GB 7718 — National food safety standard — General standard for the labelling of pre-packaged foods (食品安全国家标准 预包装食品标签通则);

z) GB/T 30766 — Tea classification (茶叶分类);

aa) ICO Std 2002 Core Layer (Chapters 4 through 10).

SE-12.3 Indicator System

SE-12.3.1 Indicator Hierarchy

The tea indicator system shall be organised into the following three-level hierarchy:

a) Level 1 — Dimensions: Sensory Quality, Physicochemical Indicators, Origin and Cultivar, Craftsmanship and Grade, Safety and Compliance, Sustainability;

b) Level 2 — Sub-dimensions: Decompositions of each dimension as specified in SE-12.3.2 through SE-12.3.7;

c) Level 3 — Specific measures: Operationalised variables for which data is collected, as specified in each sub-dimension.

SE-12.3.2 Sensory Quality (Weight: 0.30)

Sensory quality is the primary dimension for tea evaluation. The ranking entity shall conduct sensory evaluation in accordance with GB/T 23776, using the standardised scoring methodology. Evaluation conditions shall conform to GB/T 23776 requirements: tea-to-water ratio 1:50 (mass ratio), standard white porcelain evaluation cup and bowl set, controlled water temperature and infusion time per tea type.

a) Dry Tea Appearance (干茶外形): Visual assessment of the uninfused tea:

1) shape and twist (条索/外形): tightness, uniformity, and characteristic shape for the declared variety. Sensory focus varies by category:

2) colour (色泽): hue and lustre appropriate to the tea type, with sub-category differentiation:

3) integrity (整碎): proportion of whole, unbroken leaves versus fragments;

4) cleanliness (净度): absence of stems, fibre, dust, or foreign matter.

b) Liquor Colour (汤色): Visual assessment of the brewed tea liquor:

1) hue appropriate to the declared category, with differentiation:

2) clarity and brilliance (清澈度/明亮度);

3) absence of cloudiness or sediment.

c) Aroma (香气): Olfactory assessment of dry leaf, wet leaf, and liquor:

1) aroma type: conformity to the characteristic aroma, with category-specific emphasis:

2) purity: absence of off-odours (smoky, musty, stale, fire-scorched, or foreign odours);

3) persistence: the duration of aroma across multiple infusions (particularly critical for oolong and rock teas).

d) Taste and Mouthfeel (滋味): Gustatory assessment:

1) intensity (浓度): strength and depth of flavour;

2) fullness (厚度): perceived body and richness on the palate;

3) hui gan (回甘): the quality and persistence of sweet aftertaste;

4) freshness (鲜爽度): particularly important for green and white teas;

5) astringency and bitterness transformation (化苦/化涩): whether harsh notes transform positively;

6) category-specific taste characteristics:

e) Wet Leaf (叶底): Assessment of spent leaves:

1) tenderness (嫩度): proportion of buds and young leaves;

2) colour uniformity (色泽匀度): consistency indicating uniform processing;

3) integrity and flexibility: whole, unbroken leaves with appropriate elasticity;

4) category-specific wet leaf characteristics:

SE-12.3.3 Physicochemical Indicators (Weight: 0.20)

Physicochemical indicators provide objective, measurable parameters that complement sensory evaluation.

a) General Quality Parameters (applicable to all tea types):

1) moisture content (水分): shall comply with the limits specified in the applicable product standard. Typical limits: ≤7.0% for green tea (GB/T 14456), ≤6.5% for yellow tea bud type, ≤12.0% for dark tea loose-leaf, ≤14.0% for compressed dark tea;

2) total ash (总灰分): indicative of mineral content and potential adulteration. Typical limits: ≤7.0% for most tea types, ≤8.0% for dark tea;

3) water extract (水浸出物): the soluble solids yield, indicating brew strength, measured per GB/T 8305. Minimum limits vary: ≥34.0% for green tea, ≥32.0% for yellow tea, ≥28.0% for Pu-erh (GB/T 22111);

4) crude fibre (粗纤维): indicative of leaf maturity and processing quality;

5) powder content (粉末): per GB/T 8311, relevant for grading.

b) Bioactive Compound Analysis:

1) tea polyphenols (茶多酚): total polyphenol content, measured per GB/T 8313. Particularly important for green tea (≥11.0% per GB/T 14456.1); Pu-erh ripe tea limits ≤15.0% due to fermentation degradation;

2) catechins (儿茶素): individual catechin composition (EGCG, EGC, ECG, EC) measured per GB/T 8313, providing quality differentiation for green and white teas;

3) caffeine (咖啡碱): caffeine content for quality characterisation and consumer information;

4) L-theanine (茶氨酸): theanine content, a key contributor to umami taste, particularly important for shaded teas and high-grade green/white teas;

5) theaflavins (茶黄素) and thearubigins (茶红素): for black tea, the ratio of theaflavins to thearubigins is a critical quality indicator; for dark tea, changes in these compounds during post-fermentation provide maturity markers;

6) category-specific markers:

c) Pesticide Residue Limits: The ranking entity shall verify compliance with:

1) GB 2763 (national maximum residue limits);

2) EU Regulation 396/2005 (EU MRLs), for products marketed in or exported to the European Union;

3) Japan Positive List System, for products exported to Japan;

4) where multiple standards apply, the most stringent standard shall be the benchmark.

d) Heavy Metal Limits: Compliance with GB 2762:

1) lead (Pb): ≤5.0 mg/kg for tea leaves;

2) arsenic (As): compliance with applicable limits;

3) cadmium (Cd), mercury (Hg) as applicable;

4) for brick tea: fluoride (F) per GB 19965.

SE-12.3.4 Origin and Cultivar (Weight: 0.20)

This dimension evaluates the geographic origin, terroir, and cultivar identity of the tea.

a) Geographic Indication Status: The tea’s geographic origin protection:

1) national GI registration (地理标志产品) status. Key GI-designated teas and their protection scope include:

2) recognised sub-appellations (小产区) within broader GI regions (e.g., Niu Lan Keng/牛栏坑, Ma Feng/马头岩 within Wuyi Rock Tea; Shi/狮, Long/龙, Yun/云, Hu/虎, Mei/梅 within West Lake Longjing).

b) Altitude and Microclimate: Environmental factors:

1) cultivation altitude: higher altitudes generally associated with enhanced amino acid content and more complex aromas (e.g., Gaoshan tea/高山茶 in Taiwan, Wuyi mountain terrain);

2) microclimatic conditions: temperature variation, rainfall, fog frequency;

3) seasonal characteristics: pre-Qingming (明前), pre-Guyu (雨前), summer, autumn harvests.

c) Soil Characteristics:

1) soil type: weathered rock/mineral-rich soil for Wuyi rock tea (contributing to “rock rhyme/岩韵”), red laterite soil for Yunnan Pu-erh, loess soil for certain green tea areas;

2) mineral composition and its documented influence on tea character;

3) soil management and sustainability practices.

d) Cultivar Purity and Suitability:

1) declared cultivar verification. Key variety-specific standards:

2) molecular (DNA) identification where necessary for cultivar authentication;

3) cultivar suitability for the declared tea type and production area.

SE-12.3.5 Craftsmanship and Grade (Weight: 0.15)

This dimension evaluates the production process and grade classification accuracy.

a) Processing Methodology Compliance: Critical processing steps by category:

1) green tea: kill-green (杀青) method differentiation is fundamental:

2) black tea: withering (萎凋), rolling/CTC, controlled oxidation (发酵) — temperature, humidity, duration; drying;

3) oolong tea: sun-withering (晒青), indoor withering and shaking (做青/摇青) — the most technically demanding step controlling partial oxidation; kill-green; rolling; roasting (炭焙) for rock teas — degree of roast from light (清香型) to heavy (浓香型/传统型);

4) white tea: natural withering (萎凋) under controlled conditions — duration and method (indoor/outdoor/solar) critically affect quality; low-temperature drying;

5) yellow tea: the men huang/闷黄 (sealed yellowing) process — the defining step, requiring precise temperature and humidity control to produce the characteristic yellow colour and sweet taste;

6) dark tea: pile fermentation (渥堆) for ripe Pu-erh — microbial ecology management; “golden flower” cultivation (发花) for Fu brick — temperature, moisture, and timing control for Eurotium cristatum growth; aging/陈化 management for aged teas.

b) Grade Classification Accuracy:

1) grade assignment shall be based on sensory and physicochemical criteria defined in the applicable national standard (e.g., GB/T 14456 for green tea: 特级, 一级 through 五级; GB/T 22291 for white tea: Silver Needle/White Peony/Gongmei grades);

2) the ranking entity shall independently verify grade through its own sensory evaluation;

3) discrepancies between declared grade and independently assessed grade shall be documented and scored.

c) Batch Consistency: Quality consistency across production batches:

1) inter-batch sensory consistency;

2) inter-batch physicochemical parameter variation;

3) quality control system documentation.

SE-12.3.6 Safety and Compliance (Weight: 0.10)

a) Pesticide Residue International Compliance: Beyond GB 2763 compliance:

1) compliance with EU Regulation 396/2005;

2) compliance with Japan’s Positive List System;

3) compliance with Codex Alimentarius MRL standards;

4) the most stringent applicable standard shall be the benchmark.

b) Organic Certification Authenticity: For products marketed as organic:

1) verification of valid certification (GB/T 19630 for China, EU Organic per Regulation (EU) 2018/848, USDA NOP);

2) residue testing consistent with organic status;

3) annual surveillance audit results.

c) Food Safety Management Systems:

1) HACCP certification or equivalent;

2) ISO 22000 certification;

3) GMP compliance documentation.

d) Labelling Compliance: GB 7718 and tea-specific requirements:

1) accurate product category designation per GB/T 30766;

2) origin and cultivar declaration accuracy;

3) grade marking accuracy;

4) production date, shelf life, and storage instructions per GB/T 30375.

SE-12.3.7 Sustainability (Weight: 0.05)

a) Tea Garden Ecological Management: biodiversity management, IPM adoption, soil conservation, water efficiency.

b) Carbon Footprint: GHG emissions per unit of tea, renewable energy adoption, processing energy efficiency.

c) Fair Trade and Community Impact: fair trade certification, worker welfare, smallholder support, community development.

SE-12.4 Data Collection

SE-12.4.1 Data Source Categories

The ranking entity shall collect data from:

a) Sensory Panel Data: per GB/T 23776;

b) Laboratory Testing Data: from ISO/IEC 17025 accredited laboratories;

c) Garden and Factory Audit Data: on-site audit records;

d) Certification and Regulatory Records: organic certification, GI registration, food safety system certifications;

e) Market and Trade Data: market price data, auction records, brand reputation surveys.

SE-12.4.2 Sensory Panel Requirements

a) The ranking entity shall convene a panel of no fewer than five trained assessors per tea category, holding recognised qualifications (e.g., national-level tea evaluator certification 国家级茶叶审评师).

b) Evaluations shall be conducted under standardised conditions: standardised brewing parameters per GB/T 23776, standard white porcelain cup and bowl set (审评杯碗), controlled environment.

c) For each tea type, the panel shall apply the specific scoring criteria defined in the applicable national standard.

SE-12.4.3 Category-Specific Data Requirements

a) For each tea category, the ranking entity shall define category-specific data requirements:

1) Green tea: harvest date classification (明前/雨前/谷雨), kill-green method, cultivar, production area (GI designation);

2) Black tea: cultivar, harvest season, oxidation level, CTC vs. orthodox, origin (e.g., Qimen, Yunnan for Dian Hong);

3) Oolong tea: cultivar, harvest season, oxidation level, roasting degree, origin sub-appellation (e.g., Zhengyan/正岩, Banyan/半岩, Zhoucha/洲茶 for Wuyi);

4) White tea: harvest season, cultivar, production area (Fuding vs. Zhenghe), aging duration for aged white tea;

5) Yellow tea: men huang process parameters, origin;

6) Dark tea: raw material source, pile fermentation parameters, aging duration, production area, “golden flower” presence and density for Fu-type;

7) Scented tea: flower type, quality, number of scenting cycles (窨次), tea base grade;

8) Compressed tea: raw material grade, compression method, form (tuo/cake/brick), aging potential;

9) Herbal infusions: botanical species verification, origin, active compound profile.

SE-12.5 Anti-Counterfeiting and Authentication

SE-12.5.1 General Requirements

The ranking entity shall implement anti-counterfeiting mechanisms. Origin fraud, cultivar substitution, and grade inflation are prevalent in the tea market; authentication measures are mandatory.

SE-12.5.2 Origin Authentication

a) The ranking entity shall verify geographic origin through:

1) GI registration verification;

2) supply chain traceability from garden to finished product;

3) multi-element stable isotope or chemical fingerprint analysis where applicable;

4) satellite imagery and garden area verification for volume consistency.

b) Products with false origin claims shall be excluded from the ranking.

SE-12.5.3 Cultivar and Harvest Date Verification

a) For cultivar-specific claims (e.g., Tieguanyin, Longjing 43, Da Hong Pao): morphological assessment and DNA barcoding where necessary.

b) For harvest date claims (e.g., 明前茶): cross-verification against regional harvest calendars; amino acid to polyphenol ratio as indirect evidence.

SE-12.5.4 Aged Tea Authentication

a) For aged teas (aged Pu-erh, aged white tea): production date records, sensory indicators of natural aging, chemical age markers, storage condition documentation.

b) Products with unverifiable age claims shall be flagged and scored conservatively.

SE-12.6 Scoring Methodology

SE-12.6.1 Scoring Scale

a) Each Level 3 indicator shall be scored on a normalised scale from 0 to 100.

b) Quantitative indicators: min-max or z-score method per Chapter 8 of the core layer.

c) Qualitative indicators: defined ordinal scales with documented anchor descriptions.

d) Sensory indicators: 100-point scoring sheet per GB/T 23776, with category-specific weight allocations.

SE-12.6.2 Weighting

Dimension Default Weight
Sensory Quality 0.30
Physicochemical Indicators 0.20
Origin and Cultivar 0.20
Craftsmanship and Grade 0.15
Safety and Compliance 0.10
Sustainability 0.05

a) For herbal infusions (代用茶), adjusted weights shall apply per SE-12.X.

b) Products lacking food safety certification or non-compliant with GB 2762 or GB 2763 shall receive Safety and Compliance score of zero and shall be excluded.

SE-12.6.3 Aggregation

a) Level 3 to Level 2, and Level 2 to Level 1: weighted sum method per Chapter 8.

b) Overall product score: weighted sum of Level 1 dimension scores.

c) Dimension-level scores shall be reported alongside overall scores.

SE-12.7 Alignment with International Standards

SE-12.7.1 ISO Tea Standards Alignment

The Physicochemical Indicators dimension shall be consistent with ISO 3720:2011 (Black tea), ISO 11287:2011 (Green tea), and ISO 7516:2011 (Instant tea). Test methods shall be consistent with referenced ISO methods or documented equivalence shall be provided.

SE-12.7.2 Food Safety Alignment

The Safety and Compliance dimension shall be consistent with Codex Alimentarius standards, HACCP principles, and ISO 22000:2018.

SE-12.8 Publication and Transparency

SE-12.8.1 Publication Requirements

Tea ranking publications shall include:

a) tea category definitions and inclusion criteria;

b) declared origin, cultivar, and harvest season for each ranked product;

c) authentication verification results summary;

d) sensory panel composition and methodology;

e) category-specific scoring adjustments;

f) pesticide residue testing results summary.

SE-12.8.2 Product Identification

Each ranked product shall be uniquely identified by:

1) product name and declared grade;

2) producer or brand name;

3) declared production area (to the most specific appellation);

4) declared cultivar;

5) declared harvest season and year;

6) declared processing method.

SE-12.X Sub-Module: Herbal Infusions (代用茶)

SE-12.X.1 Scope and Definition

This sub-module applies to herbal infusions (代用茶): plant-based materials not derived from Camellia sinensis, intended for infusion or decoction. The fundamental distinction from true tea is the absence of tea-specific compounds (polyphenols, caffeine, theanine).

a) Category coverage:

1) flower-based (花类): chrysanthemum (菊花 — Hangbaiju/杭白菊 ref: GB/T 18862, Boju/亳菊, Chuju/滁菊, Gongju/贡菊, wild chrysanthemum/野菊花), honeysuckle (金银花), rose (玫瑰花), osmanthus (桂花), sophora flower (槐花);

2) fruit-based (果类): goji berry (枸杞 ref: GB/T 18672), monk fruit (罗汉果 ref: GB/T 20357), hawthorn (山楂);

3) leaf/herb-based (叶/草类): lotus leaf (荷叶), tartary buckwheat (苦荞 ref: GB/T 10458), buckwheat (荞麦), cassia seed (决明子), peppermint (薄荷), perilla (紫苏);

4) root/rhizome-based (根茎类): licorice (甘草 ref: GB/T 19618), kudzu root (葛根);

5) other: mulberry leaf (桑叶), eucommia (杜仲), corn silk (玉米须).

b) Products combining herbal infusion materials with true tea shall be evaluated under re-processed tea provisions rather than this sub-module.

SE-12.X.2 Sensory Evaluation Methodology for Herbal Infusions

a) Sensory evaluation differs from true tea:

1) dry material appearance: colour uniformity, integrity, cleanliness, species-characteristic appearance;

2) infusion colour: colour appropriate to botanical material;

3) aroma: characteristic botanical aroma, purity, absence of off-odours (sulphur residue, mould);

4) taste: characteristic flavour, sweetness, bitterness specific to species;

5) spent material: species verification and quality indicators.

b) Traditional tea scoring criteria (GB/T 23776) do not apply directly. Category-specific sensory scoring sheets shall be developed.

SE-12.X.3 Physicochemical Parameters for Herbal Infusions

a) The indicator system replaces tea-specific parameters with botanical-active compounds:

1) moisture content: shall comply with applicable limits for dried botanicals;

2) total ash: cleanliness and adulteration indicator;

3) category-specific active compounds:

Botanical Key Markers Applicable Standard
Chrysanthemum (菊花) total flavonoids (总黄酮), chlorogenic acid (绿原酸) GB/T 18862
Goji berry (枸杞) polysaccharides (多糖), betaine (甜菜碱), zeaxanthin (玉米黄质) GB/T 18672
Monk fruit (罗汉果) mogrosides (罗汉果苷), particularly mogroside V GB/T 20357
Honeysuckle (金银花) chlorogenic acid (绿原酸), luteoloside (木犀草苷) —
Tartary buckwheat (苦荞) rutin (芦丁), total flavonoids GB/T 10458
Cassia seed (决明子) anthraquinone derivatives (蒽醌类) —

b) The ranking entity shall identify and measure primary bioactive markers using validated analytical methods.

SE-12.X.4 Safety Evaluation for Herbal Infusions

a) Specific hazards for herbal infusions:

1) sulphur dioxide (SO₂): many herbal infusions are susceptible to sulphur fumigation. The ranking entity shall measure SO₂ residues and ensure compliance with GB 2760 limits. Excessive residuals shall result in significant safety score deduction;

2) microbiological limits: total plate count, coliforms, mould and yeast counts;

3) heavy metals: Pb, Cd, As, Hg per GB 2762;

4) pesticide residues: per GB 2763;

5) adulteration detection: species identity verification through macroscopic/microscopic examination and DNA barcoding where necessary.

b) The ranking entity shall assign a dedicated safety sub-score weighing SO₂ and microbiological safety more heavily than for true tea.

SE-12.X.5 Category Classification and Evaluation Framework

a) Evaluation shall be within declared botanical category with category-specific benchmarks:

1) quality grade criteria: premium, standard, acceptable grades per botanical;

2) origin benchmarks: recognised production areas (e.g., Hangzhou for Hangbaiju/杭白菊, Zhongwei/Ningxia for Boju/亳菊, Chuzhou for Chuju/滁菊);

3) processing standards: drying method (air-dried, freeze-dried, oven-dried), cleaning, sorting;

4) authenticity markers: species-specific identification and adulteration detection protocols.

Note: This extension module is part of ICO Std 2002 (Tianji Ranking Methodology Standard). Tea rankings carry significant cultural and economic weight, particularly in major tea-producing countries. Ranking entities shall respect the diversity of tea traditions while maintaining rigorous scientific standards. Particular attention shall be paid to: (a) pesticide residue compliance, as tea is consumed as an infusion where residues may be extracted into the drinking water; (b) geographic indication integrity, as origin fraud is prevalent in the specialty tea market; and (c) accurate grade classification, as grade inflation is a widespread issue. For herbal infusions, sulphur fumigation and botanical authenticity are the primary safety concerns.