SIST ISO 6673:2026

• Abstract:

  This document specifies a method for the determination of the loss in mass at 105 °C of green coffee. ; This document is applicable to decaffeinated and non-decaffeinated green coffee as defined in ISO 3509. ; This method of determining the loss in mass can be considered, by convention, as a method for determining the water content and can be used as such by agreement between the interested parties. This method serves as a reference method for calibrating methods of determining the water content.

• Status: Published
• Publication Date: 08-Oct-2026
• ICS: 67.140.20 - Coffee and coffee substitutes
• Technical Committee: KŽP - Agricultural food products
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 06-Oct-2026
• Due Date: 11-Dec-2026
• Completion Date: 09-Oct-2026
• Ref Project: ISO 6673:2025 - Green coffee — Determination of loss in mass at 105 °C

• Replaces: SIST ISO 6673:2011 - Green coffee -- Determination of loss in mass at 105 degrees C
• Effective Date: 01-Nov-2026

SIST ISO 6673:2026 is the Slovenian standard identical to ISO 6673:2025, published by SIST. It specifies a laboratory method for determining the loss in mass at 105 °C of green coffee, and by agreement it can also be used as a reference way to estimate water content in decaffeinated and non-decaffeinated green coffee.

What does SIST ISO 6673:2026 specify?

SIST ISO 6673:2026 specifies a gravimetric method for green coffee dried at 105 °C. It is intended for decaffeinated and non-decaffeinated green coffee as defined in ISO 3509, and it can serve as a reference method when laboratories calibrate water-content methods.

The document is organized into clauses on:

• scope
• normative references
• terms and definitions
• principle
• apparatus
• sampling
• procedure
• expression of results
• uncertainty
• precision
• test report

That structure matters in practice because it takes the user from sample handling through calculation and reporting, so a laboratory can run the same method and document it in a consistent way.

What are the key requirements of SIST ISO 6673:2026?

The core of SIST ISO 6673:2026 is a controlled drying-and-weighing test. The result is based on how much mass a prepared coffee sample loses after heating under specified conditions.

Drying conditions and principle

Clause 4 states that the test portion is heated at 105 °C ± 1 °C for 16 h ± 0.5 h at atmospheric pressure. In practice, this means the oven temperature and time must be controlled closely, because the result depends on removing water and other volatile matter in a repeatable way.

Apparatus and measurement setup

Clause 5 requires an electrically heated oven with forced ventilation and calibration in the useful volume, a dish with a close-fitting lid, an analytical balance readable to 0.1 mg, and a desiccator with an efficient desiccant. An optional thermometer may be used. This matters because the method is sensitive to temperature, moisture uptake and weighing precision.

Sampling and sample integrity

Clause 6 states that the laboratory should receive a sample that is representative and has not been damaged or changed during transport or storage. Sampling is not part of the method, and ISO 4072 is given as a recommended sampling method. In practice, this means the test result is only as good as the condition of the sample delivered to the lab.

Preparing, loading and drying the dish

Clause 7.1 requires the dish and lid to be dried for 1 h at 105 °C, cooled in a desiccator and weighed. Clause 7.2 then calls for about 10 g of coffee spread uniformly in the dish, with quick handling to avoid moisture loss or pickup. This reduces handling error and keeps the starting mass stable.

Number of determinations

Clause 7.4 requires three determinations on the same test sample. For the user, that means the report should be based on replicate results, not a single measurement.

Calculating and averaging the result

Clause 8 gives the calculation of loss in mass at 105 °C as a percentage by mass and states that the final result is the arithmetic mean of the three determinations. That provides one reported value for routine use and for comparison between laboratories.

Uncertainty, precision and reporting

Clause 9 requires uncertainty to be determined in accordance with ISO/IEC Guide 98-3:2008 and says to consider repeatability, weighing, drying time and intermediate precision. Clause 10 summarizes interlaboratory precision data in Table 1. Clause 11 lists the information that must appear in the test report, including sample identification, method reference, deviations, incidents and results with units.

What terms does SIST ISO 6673:2026 define?

• Loss in mass at 105 °C - the mass lost during drying, made up mainly of water and small amounts of volatile matter, expressed as a percentage by mass.
• Green coffee - coffee in the unroasted state, using the vocabulary of ISO 3509.
• Test portion - the portion of sample placed in the dish for drying and weighing.
• Repeatability - the closeness of results under the same test conditions, reflected in Clause 10.
• Reproducibility - the closeness of results between laboratories, also summarized in Clause 10.
• GUM - the Guide to the Expression of Uncertainty in Measurement, cited through ISO/IEC Guide 98-3:2008.

Who uses SIST ISO 6673:2026?

SIST ISO 6673:2026 is used by laboratories that test green coffee quality, especially where moisture or dry matter needs to be measured by a reference method. It is also useful for quality managers, coffee traders and buyers who need a common test basis in agreements between interested parties.

It is particularly relevant when a laboratory must calibrate or check another method for water-content determination. The reporting requirements also make it useful for teams that need traceable, comparable test records.

What changed in SIST ISO 6673:2026 from the previous edition?

SIST ISO 6673:2026 replaces SIST ISO 6673:2011. The ISO third edition that underlies this text cancels and replaces ISO 6673:2003 and states these changes:

• the number of determinations on the same test sample was changed
• Clause 9 on uncertainty was added
• the test report clause was renumbered and updated

Which standards are used with SIST ISO 6673:2026?

Standard	What it contributes
ISO 3509	Vocabulary for coffee and coffee products, including the terms used for green coffee
ISO/IEC Guide 98-3:2008	The framework for evaluating measurement uncertainty
ISO 4072	A recommended sampling method for green coffee in bags
ISO 5725:1986	The statistical basis used for the interlaboratory precision data in Clause 10

What does the SIST ISO 6673:2026 document contain?

SIST ISO 6673:2026 contains a step-by-step laboratory method, a calculation formula for loss in mass at 105 °C, and a precision table based on an interlaboratory test. It also includes the apparatus list, the dish-preparation procedure, the drying and weighing sequence, and the required content of the test report.

Clause 10 provides the statistical precision results, while Clause 8 provides the calculation approach used to turn masses into a percentage result. The document is therefore useful both for routine testing and for method validation, calibration and audit records.

SLOVENSKI STANDARD
01-november-2026
Nadomešča:
SIST ISO 6673:2011
Surova kava - Določanje izgube mase pri 105 °C (ISO 6673:2025)
Green coffee — Determination of loss in mass at 105 °C (ISO 6673:2025)
Café vert — Détermination de la perte de masse à 105 °C (ISO 6673:2025)
Ta slovenski standard je istoveten z: ISO 6673:2025
ICS:
67.140.20 Kava in kavni nadomestki Coffee and coffee substitutes
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

International
Standard
ISO 6673
Third edition
Green coffee — Determination of
2025-11
loss in mass at 105 °C
Café vert — Détermination de la perte de masse à 105 °C
Reference number
© ISO 2025
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Apparatus . 1
6 Sampling . 2
7 Procedure . 2
7.1 Preparation of the dish.2
7.2 Test portion .2
7.3 Determination .2
7.4 Number of determinations .3
8 Expression of results . 3
9 Uncertainty . 3
10 Precision . 3
11 Test report . 4
Bibliography . 5

iii
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee
has been established has the right to be represented on that committee. International organizations,
governmental and non-governmental, in liaison with ISO, also take part in the work. 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 document 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).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and 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 15, Coffee.
This third edition cancels and replaces the second edition (ISO 6673:2003), which has been technically
revised.
The main changes are as follows:
— the number of determinations to be carried out on the same
...

International
Standard
ISO 6673
Third edition
Green coffee — Determination of
2025-11
loss in mass at 105 °C
Café vert — Détermination de la perte de masse à 105 °C
Reference number
© ISO 2025
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Apparatus . 1
6 Sampling . 2
7 Procedure . 2
7.1 Preparation of the dish.2
7.2 Test portion .2
7.3 Determination .2
7.4 Number of determinations .3
8 Expression of results . 3
9 Uncertainty . 3
10 Precision . 3
11 Test report . 4
Bibliography . 5

iii
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee
has been established has the right to be represented on that committee. International organizations,
governmental and non-governmental, in liaison with ISO, also take part in the work. 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 document 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).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and 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 15, Coffee.
This third edition cancels and replaces the second edition (ISO 6673:2003), which has been technically
revised.
The main changes are as follows:
— the number of determinations to be carried out on the same test sample has been changed;
— Clause 9 on uncertainty been added;
— the renumbered Clause 11 for the test report has been updated.
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
...