SIST EN ISO 712:2010

SLOVENSKI STANDARD
SIST EN ISO 712:2010
01-marec-2010
äLWRLQSURL]YRGLL]åLWD'RORþHYDQMHYVHEQRVWLYODJH5HIHUHQþQDPHWRGD,62

Cereals and cereal products - Determination of moisture content - Reference method
(ISO 712:2009)
Getreide und Getreideerzeugnisse - Bestimmung des Feuchtegehaltes -
Referenzverfahren (ISO 712:2009)
Céréales et produits céréaliers - Détermination de la teneur en eau - Méthode de
référence (ISO 712:2009)
Ta slovenski standard je istoveten z: EN ISO 712:2009
ICS:
67.060 äLWDVWURþQLFHLQSURL]YRGLL] Cereals, pulses and derived
QMLK products
SIST EN ISO 712:2010 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 712:2010

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SIST EN ISO 712:2010


EUROPEAN STANDARD
EN ISO 712

NORME EUROPÉENNE

EUROPÄISCHE NORM
November 2009
ICS 67.060
English Version
Cereals and cereal products - Determination of moisture content
- Reference method (ISO 712:2009)
Céréales et produits céréaliers - Détermination de la teneur Getreide und Getreideerzeugnisse - Bestimmung des
en eau - Méthode de référence (ISO 712:2009) Feuchtegehaltes - Referenzverfahren (ISO 712:2009)
This European Standard was approved by CEN on 14 November 2009.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national
standards may be obtained on application to the CEN Management Centre or to any CEN member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as the
official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.






EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2009 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 712:2009: E
worldwide for CEN national Members.

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SIST EN ISO 712:2010
EN ISO 712:2009 (E)
Contents Page
Foreword .3

2

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SIST EN ISO 712:2010
EN ISO 712:2009 (E)
Foreword
This document (EN ISO 712:2009) has been prepared by Technical Committee ISO/TC 34 "Food products" in
collaboration with Technical Committee CEN/TC 338 “Cereal and cereal products” the secretariat of which is
held by AFNOR.
This European Standard shall be given the status of a national standard, either by publication of an identical
text or by endorsement, at the latest by May 2010, and conflicting national standards shall be withdrawn at the
latest by May 2010.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech
Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the United Kingdom.
Endorsement notice
The text of ISO 712:2009 has been approved by CEN as a EN ISO 712:2009 without any modification.


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SIST EN ISO 712:2010

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SIST EN ISO 712:2010

INTERNATIONAL ISO
STANDARD 712
Fourth edition
2009-11-15


Cereals and cereal products —
Determination of moisture content —
Reference method
Céréales et produits céréaliers — Détermination de la teneur en eau —
Méthode de référence





Reference number
ISO 712:2009(E)
©
ISO 2009

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SIST EN ISO 712:2010
ISO 712:2009(E)
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©  ISO 2009
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
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ii © ISO 2009 – All rights reserved

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SIST EN ISO 712:2010
ISO 712:2009(E)
Contents Page
Foreword .iv
1 Scope.1
2 Terms and definitions .1
3 Principle.1
4 Apparatus.1
5 Sampling.2
6 Preparation of the test sample.2
6.1 Products not requiring grinding .2
6.2 Products requiring grinding.3
6.2.1 General .3
6.2.2 Grinding without preconditioning .3
6.2.3 Grinding with preconditioning .3
7 Procedure.3
7.1 Number of determinations.3
7.2 Test portion.3
7.3 Drying .4
7.4 Weighing.4
8 Expression of results.4
8.1 Without preconditioning.4
8.2 With preconditioning.4
9 Precision.5
9.1 Interlaboratory test.5
9.2 Repeatability .5
9.3 Reproducibility .5
9.4 Comparison of two groups of measurements in one laboratory .5
9.5 Comparison of two groups of measurements in two laboratories.6
9.6 Uncertainty.6
10 Test report.6
Annex A (informative) Results of interlaboratory test .7
Annex B (informative) Cereals and cereal products — Determination of moisture content
Absolute method .9
Bibliography.16

© ISO 2009 – All rights reserved iii

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SIST EN ISO 712:2010
ISO 712:2009(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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
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.
ISO 712 was prepared by Technical Committee ISO/TC 34, Food products, Subcommittee SC 4, Cereals and
pulses.
This fourth edition cancels and replaces the third edition (ISO 712:1998), which has been technically revised.

iv © ISO 2009 – All rights reserved

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SIST EN ISO 712:2010
INTERNATIONAL STANDARD ISO 712:2009(E)

Cereals and cereal products — Determination of moisture
content — Reference method
1 Scope
This International Standard specifies a routine reference method for the determination of the moisture content
of cereals and cereal products.
This International Standard applies to: wheat, rice (paddy, husked and milled), barley, millet (Panicum
miliaceum), rye, oats, triticale, sorghum in the form of grains, milled grains, semolina or flour.
The method is not applicable to maize and pulses.
[5] [7]
NOTE For moisture content determination in maize, see ISO 6540 ; and for pulses, see ISO 24557 .
2 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
2.1
moisture content
mass loss undergone by a product under the conditions specified in this International Standard
NOTE Moisture content is expressed as a percentage.
3 Principle
If necessary, a laboratory sample is ground, after conditioning, if required. A test portion is dried at a
temperature between 130 °C and 133 °C, under conditions which enable a result to be obtained which
corresponds to that obtained by the absolute method described in Annex B.
4 Apparatus
4.1 Analytical balance, capable of weighing to an accuracy of ± 0,001 g.
4.2 Grinding mill, having the following characteristics:
a) made of material which does not absorb moisture;
b) easy to clean and having as little dead space as possible;
c) enabling grinding to be carried out rapidly and uniformly, without appreciable development of heat
(difference of temperatures before and after grinding smaller than or equal to 5 °C);
NOTE A grinding mill fitted with a cooling device can comply with this requirement.
d) tightness to air to avoid water exchange between sample and external air;
e) adjustable so as to obtain particles of the dimensions indicated in Table 1.
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SIST EN ISO 712:2010
ISO 712:2009(E)
4.3 Metal dish, non-corrodible under the test conditions, or glass dish, with a lid and having an effective
surface area enabling the test portion to be distributed so as to give a mass per unit area of not more than
2
0,3 g/cm .
4.4 Constant-temperature oven, electrically heated, controlled in such a way that, during normal working,
the temperature of the air and of the shelves carrying the test portions is maintained within the range 130 °C
to 133 °C in the vicinity of the test portions.
The oven shall have a heat capacity such that, when initially adjusted to a temperature of 131 °C, it can regain
this temperature in less than 30 min after insertion of the maximum number of test portions that can be dried
simultaneously.
The effectiveness of the ventilation shall be determined using durum wheat semolina, of maximum particle
size of 1 mm, as the test material. The ventilation shall be such that, after insertion of the maximum number of
test portions that the oven can accommodate, and drying at a temperature of 130 °C to 133 °C, the results,
after heating the same test portions for 2 h and then for a further 1 h, do not differ by more than 0,15 g of
moisture per 100 g of sample.
4.5 Desiccator, containing an effective desiccant.
5 Sampling
Sampling is not part of the method specified in this International Standard. A recommended sampling method
[6]
is given in ISO 24333 .
A representative sample, in an airtight packaging, should have been sent to the laboratory. It should not have
been damaged or changed during transport or storage.
6 Preparation of the test sample
6.1 Products not requiring grinding
Products having particle size characteristics indicated in Table 1 do not need to be ground before the
determination.
Mix the laboratory sample thoroughly before taking the test portion (7.2).
Table 1 — Particle size characteristics of products not requiring grinding
Particle size characteristics Proportion
mm %
a
u 1,7 (1,8) 100
b
> 1,0 (1,0) u 10
a
< 0,5 (0,56) W 50
a
[1]
Nominal size of openings, ISO 3310-1 , that does not retain this particle size.
b
[1]
Nominal size of openings, ISO 3310-1 , that retains this particle size.

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SIST EN ISO 712:2010
ISO 712:2009(E)
6.2 Products requiring grinding
6.2.1 General
If the products do not have the particle size characteristics mentioned in Table 1, they shall be ground either
without preconditioning (6.2.2) or with preconditioning (6.2.3), as required.
6.2.2 Grinding without preconditioning
For products that are not likely to undergo variations in moisture content during grinding (in general, products
with a moisture content between 9 % and 15 %), grind without preconditioning.
NOTE The range of moisture contents given for conditioning products before grinding corresponds approximately in
the laboratory to a temperature of 20 °C and a relative humidity of 40 % to 70 %.
Adjust the grinding mill (4.2) to obtain particles of the dimensions indicated in Table 1.
Then, quickly grind a quantity of the laboratory sample according to the apparatus used and at least slightly
greater than that required for the test portion (about 5 g), and immediately proceed in accordance with 7.2.
6.2.3 Grinding with preconditioning
Products which are likely to undergo changes in moisture content during the course of grinding (in general,
products with a moisture content greater than 15 % or less than 9 %) shall be preconditioned so as to bring
their moisture content to between 9 % and 15 % before grinding.
If the moisture content is more than 15 % (the most frequent case), weigh, to the nearest 0,001 g, a sufficient
quantity of the laboratory sample to provide a test portion slightly greater than 5 g (see 6.2.2). Record the
mass of the test portion before preconditioning and dish as m' . Pre-dry in accordance with 7.3, except that
2
the time of heating in the oven (4.4) shall be 7 min to 10 min and the product shall be cooled to laboratory
temperature with the dish (4.3) uncovered and without a desiccator, for at least 2 h.
NOTE It is possible that these times are not be suitable for all products, e.g. paddy rice.
For products having moisture contents of less than 9 %, weigh, to the nearest 0,001 g, a sufficient quantity of
the laboratory sample to provide a test portion slightly greater than 5 g (see 6.2.2). Record the mass of the
test portion before preconditioning and dish as m' . Place in a suitable atmosphere (generally that of the
2
laboratory) and leave until a moisture content within the limits indicated above is obtained.
After conditioning, weigh the sample to the nearest 0,001 g. Record the mass of the test portion after
preconditioning and dish as m' . Grind immediately, adjusting the grinder so as to obtain particles of the
3
dimensions indicated in Table 1, and immediately proceed in accordance with 6.2.2.
7 Procedure
7.1 Number of determinations
Carry out separate determinations on two test portions taken from the laboratory sample in accordance with
7.2 and 7.3. If the absolute difference between the two values obtained is greater than the repeatability limit
given in Clause 9, repeat the determination until requirements are satisfied.
7.2 Test portion
Rapidly weigh, to the nearest 0,001 g, a quantity of 5 g ± 1 g of the laboratory sample (6.2.2 or 6.2.3) in the
dish (4.3). Record the mass of the undried test portion and dish as m' . Previously dry and tare the dish,
0
together with its lid, and record the mass, m , to the nearest 0,001 g.
d
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SIST EN ISO 712:2010
ISO 712:2009(E)
7.3 Drying
Place the open dish containing the test portion (7.2), together with the lid, in the oven (4.4) and leave
for 120 min ± 5 min (90 min for flours).
In certain cases and particularly in hot and dry countries, the drying period may be reduced to 60 min ± 5 min,
which is sufficient time for the test portions to attain constant mass. Review these times regularly.
Do not open the door of the oven during drying and do not place moist products in the oven before removing
the dry test portions, as this will result in partial rehydration of the latter.
After drying, quickly remove the dish from the oven, cover, and place in the desiccator (4.5). When several
tests ar
...