Coffee and coffee products — Determination of particle size of ground roasted coffee — Horizontal sieving motion method using circular brushes

This document specifies a method for carrying out particle-size distribution analysis of roasted ground coffee by horizontal sieving motion method using circular brushes to minimize the effects of obstruction, agglomeration and adhesion. It specifies general principles to follow concerning apparatus, procedure and presentation of results. This document is applicable to particle sizes ranging from approximately 150 μm to 2 mm.

Café et dérivés du café — Détermination de la taille des grains de café torréfié moulu — Méthode de tamisage horizontal à l’aide de brosses circulaires

General Information

Status
Published
Publication Date
28-Jul-2022
Technical Committee
Drafting Committee
Current Stage
6060 - International Standard published
Due Date
28-Jan-2022
Completion Date
29-Jul-2022
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ISO 23134:2022 - Coffee and coffee products — Determination of particle size of ground roasted coffee — Horizontal sieving motion method using circular brushes Released:29. 07. 2022
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INTERNATIONAL ISO
STANDARD 23134
First edition
2022-07
Coffee and coffee products —
Determination of particle size of
ground roasted coffee — Horizontal
sieving motion method using circular
brushes
Café et dérivés du café — Détermination de la taille des grains de café
torréfié moulu — Méthode de tamisage horizontal à l’aide de brosses
circulaires
Reference number
ISO 23134:2022(E)
© ISO 2022
---------------------- Page: 1 ----------------------
ISO 23134:2022(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2022

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

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Published in Switzerland
© ISO 2022 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 23134:2022(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ..................................................................................................................................................................................... 1

3 Terms and definitions .................................................................................................................................................................................... 1

4 Principle ........................................................................................................................................................................................................................ 1

5 Apparatus .................................................................................................................................................................................................................... 2

6 Sample preparation ..........................................................................................................................................................................................3

6.1 General ........................................................................................................................................................................................................... 3

6.2 Division of the sample ...................................................................................................................................................................... 3

6.3 Test sample ................................................................................................................................................................................................ 3

7 Procedure ....................................................................................................................................................................................................................3

8 Precision of the method ...............................................................................................................................................................................4

8.1 Interlaboratory test ......... ................................................................................................................................................................... 4

8.2 Repeatability ............................................................................................................................................................................................ 4

8.3 Reproducibility ....................................................................................................................................................................................... 4

9 Test report .................................................................................................................................................................................................................. 4

Annex A (informative) Precision data of the validation study on the particle sizes of ground

roasted coffee for horizontal sieving motion method using circular brushes ..................................6

Annex B (informative) Reliability of the horizontal sieving method using brushes ........................................7

Annex C (informative) Sieve size .............................................................................................................................................................................. 8

Annex D (informative) Determination of average particle size calculated by mathematical

model .............................................................................................................................................................................................................................10

Annex E (informative) Specifications and manufacturing of circular brushes ..................................................12

Bibliography .............................................................................................................................................................................................................................16

iii
© ISO 2022 – All rights reserved
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ISO 23134:2022(E)
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 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

patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www.iso.org/patents).

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.

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.
© ISO 2022 – All rights reserved
---------------------- Page: 4 ----------------------
INTERNATIONAL STANDARD ISO 23134:2022(E)
Coffee and coffee products — Determination of particle
size of ground roasted coffee — Horizontal sieving motion
method using circular brushes
1 Scope

This document specifies a method for carrying out particle-size distribution analysis of roasted

ground coffee by horizontal sieving motion method using circular brushes to minimize the effects of

obstruction, agglomeration and adhesion. It specifies general principles to follow concerning apparatus,

procedure and presentation of results.

This document is applicable to particle sizes ranging from approximately 150 μm to 2 mm.

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 565, Test sieves — Metal wire cloth, perforated metal plate and electroformed sheet — Nominal sizes

of openings
ISO 2395, Test sieves and test sieving — Vocabulary

ISO 3310-1, Test sieves — Technical requirements and testing — Part 1: Test sieves of metal wire cloth

ISO 9276-1, Representation of results of particle size analysis — Part 1: Graphical representation

ISO 9276-2, Representation of results of particle size analysis — Part 2: Calculation of average particle

sizes/diameters and moments from particle size distributions

ISO 9276-3, Representation of results of particle size analysis — Part 3: Adjustment of an experimental

curve to a reference model

ISO 9276-4, Representation of results of particle size analysis — Part 4: Characterization of a classification

process
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 2395 apply.

ISO and IEC maintain terminology databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
4 Principle

Separate a sample of roasted ground coffee by horizontal sieving machines using circular brushes on

each test sieve to obtain reliable analysis.

Annex B compares the results of the horizontal sieving method (with or without brushes) to the results

of the laser diffraction method.
© ISO 2022 – All rights reserved
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ISO 23134:2022(E)
5 Apparatus
The usual laboratory apparatus and, in particular, the following shall be used.
5.1 Horizontal sieve shaker or tap sieve shaker.

The equipment shall be provided with a timer that counts to at least 10 min, as well as all the necessary

accessories for its proper and safe functioning.
5.2 Test sieves.

The sieves given in Table 1 shall be used in accordance with ISO 565 and ISO 3310-1. It is not necessary

to use sieves smaller than 150 μm (experimental evidence for this is given in Annex C).

Test sieving shall be carried out with a single test sieve or with a series of test sieves with different

nominal aperture sizes. A lid and receiver pan should be included in both cases, where appropriate.

The number of sieves used in the test should be sufficient to give the requisite information about the

material and to avoid excessive wear or blinding.
Table 1 — Sieves’ opening in accordance with ISO 565 and ISO 3310-1
Series R 20/3 Series R 40/3
μm μm
1 400 1 180
1 000 850
710 600
500 425
355 300
250 212
180 150
5.3 Balance, capable of weighing to an accuracy of 0,1 g.

5.4 Special circular brush, with a convex or flat cap and a mass not greater than 25 g in order to

avoid possible fractionation of the material by the brush. For detailed information on the brushes and

their manufacturing, see Annex E.
A special circular brush with a cap is illustrated in Figure 1.
© ISO 2022 – All rights reserved
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ISO 23134:2022(E)
Key
a bristle brush diameter: 13 mm to 17 mm
b circular brush diameter: 80 mm to 100 mm
Figure 1 — Special circular brush with a cap
6 Sample preparation
6.1 General

The sampling method used should be such that the sample taken for sieving is truly representative of

sample material from which is has been drawn.
6.2 Division of the sample

The original sample is often too large for direct use in a sieve test: it shall therefore be reduced. In

reducing the sample, it is just as important to ensure that the final quantity (test sample) taken for

sieving is truly representative of the original sample as it is to ensure that the original sample was

representative of the material.
NOTE A precision divider can be used for this purpose.
6.3 Test sample
Take a te
...

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