ISO 3103:2019

Tea - Preparation of liquor for use in sensory tests

This document specifies a method for the preparation of a liquor of tea for use in sensory tests, by means of infusing the leaf.

Thé — Préparation d'une infusion en vue d'examens organoleptiques

General Information

• Status: Published
• Publication Date: 08-Dec-2019
• ICS: 67.140.10 - Tea
• ICS: 67.240 - Sensory analysis
• Technical Committee: ISO/TC 34/SC 8 - Tea
• Drafting Committee: ISO/TC 34/SC 8 - Tea
• Current Stage: 9093 - International Standard confirmed
• Start Date: 08-Jul-2025
• Completion Date: 13-Dec-2025

Relations

• Revises: ISO 3103:1980 - Tea - Preparation of liquor for use in sensory tests
• Effective Date: 04-Feb-2017

Overview

ISO 3103:2019 specifies a standardized method for preparing tea liquor (infused tea) for use in sensory tests. The standard defines the equipment, sample mass, water temperature, brew times and handling procedures required to produce reproducible tea samples for organoleptic evaluation. It is the 2019 second edition (technical revision) and applies to Camellia sinensis‑based teas (black and green teas) prepared by infusion.

Key topics and requirements

• Purpose: Produce reproducible tea liquor for sensory analysis (taste, aroma, appearance, infused leaf).
• Apparatus: White porcelain or glazed earthenware pot with serrated edge and loose‑fitting lid, and a white porcelain/earthenware bowl. Two recommended sizes (large and small) with specified capacities and mass tolerances.
  • Large pot capacity ≈ 310 ± 8 ml (fill ≈ 285 ml); small pot ≈ 150 ± 4 ml (fill ≈ 140 ml).
  • Recommended pot/bowl masses (for reproducible temperature profile): e.g., large pot 200 ± 10 g.
• Sample mass: 2 g of tea per 100 ml of water (weigh ±2%).
  • Typical measured doses: large pot 5.6 ± 0.1 g; small pot 2.8 ± 0.05 g.
• Water temperature and brew time:
  • Black tea: boiling water (~100 °C), brew 6 minutes.
  • Green tea: boiling water (~100 °C), leafy types 5 minutes, fannings 3 minutes.
  • Note: state altitude if boiling point is affected.
• Milk procedure (black tea only):
  • Milk free from off‑flavours; approx. 5 ml (large bowl) or 2.5 ml (small bowl).
  • Milk may be added before or after pouring liquor; if added after, liquor temperature 65–80 °C is recommended.
• Water quality: Use water similar to local drinking water; distilled/deionized water only in exceptional comparative testing (results may differ).
• Sampling and reporting:
  • Sampling per ISO 1839.
  • Test report must record mass of tea, water volume/type, pot/bowl type and dimensions, brew time, water source and temperature, milk use/volume/timing, and full sample identification.

Applications and users

ISO 3103 is used for:

• Sensory panels and professional tea tasters to ensure reproducible cupping conditions.
• Tea producers and packers for quality control and batch comparisons.
• Research laboratories conducting sensory or compositional studies on tea.
• Standards bodies and certification schemes validating organoleptic claims.

Keywords: ISO 3103, tea preparation, tea liquor, sensory tests, tea tasting, brewing procedure, black tea, green tea, tea quality control.

Related standards

• ISO 1839 - Tea - Sampling (referenced for sampling requirements)
• ISO 3720 - Black tea - Definition and basic requirements
• ISO 11287 - Green tea - Definition and basic requirements

This standard provides a clear, repeatable protocol to minimize preparation variability and support reliable sensory comparison across laboratories and organizations.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 3103
Second edition
2019-12
Tea — Preparation of liquor for use in
sensory tests
Thé — Préparation d'une infusion en vue d'examens organoleptiques
Reference number
©
ISO 2019
© ISO 2019
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
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ii © ISO 2019 – All rights reserved

Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 2
5 Apparatus . 2
6 Sampling . 2
7 Procedure. 2
7.1 Test portion . 2
7.2 Preparation of liquor . 2
7.2.1 Preparation without milk . 2
7.2.2 Preparation with milk (black tea only). 3
8 Test report . 3
Annex A (informative) Examples of pots and bowls for the preparation of tea liquor .4
Bibliography . 8
Foreword
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bodies (ISO member bodies). The work of preparing International Standards is normally carried out
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ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
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expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see www .iso .org/
iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 34 Food products, Subcommittee SC 8, Tea.
This second edition cancels and replaces the first edition (ISO 3103:1980), which has been technically
revised. The main changes compared with the previous edition are as follows.
— Revisions have been made to reflect the increasing commercial trade in different types of Camellia
sinensis-based tea. This document allows for teas where there are current International Standards
(black and green) to be assessed in a common framework with the same hardware.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.
iv © ISO 2019 – All rights reserved

INTERNATIONAL STANDARD ISO 3103:2019(E)
Tea — Preparation of liquor for use in sensory tests
1 Scope
This document specifies a method for the preparation of a liquor of tea for use in sensory tests, by
means of infusing the leaf.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 1839, Tea — Sampling
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
liquor
solution prepared by extraction of soluble substances from dried tea leaf, under the conditions
described
3.2
infused leaf
tea leaf from which liquor (3.1) has been prepared
3.3
black tea
tea derived solely
...