SIST EN ISO 1211:2010

Milk - Determination of fat content - Gravimetric method (Reference method) (ISO 1211:2010)

This International Standard specifies the reference method for the determination of the fat content of milk of good physicochemical quality. The method is applicable to raw cow milk, raw sheep milk, raw goat milk, reduced fat milk, skimmed milk, chemically preserved milk, and processed liquid milk. It is not applicable when greater accuracy is required for skimmed milk, e.g. to establish the operating efficiency of cream separators.

Milch - Bestimmung des Fettgehaltes - Gravimetrisches Verfahren (Referenzverfahren) (ISO 1211:2010)

Diese Internationale Norm legt ein Referenzverfahren zur Bestimmung des Fettgehaltes von Milch guter
physikochemischer Qualität fest.
Das Verfahren ist anwendbar auf Rohmilch, Schafsrohmilch, Ziegenrohmilch, Milch mit reduziertem
Fettgehalt, chemisch konservierte Magermilch und verarbeitete Flüssigmilch.
Falls eine größere Genauigkeit bei Magermilch benötigt wird, zum Beispiel um die Betriebsleistung von
Separatoren zu ermitteln, ist das in ISO 7208 [4] festgelegte besondere Verfahren für Magermilchprodukte
anzuwenden.

Lait - Détermination de la teneur en matière grasse - Méthode gravimétrique (Méthode de référence) (ISO 1211:2010)

L'ISO 1211|FIL 1:2010 spécifie la méthode de référence pour la détermination de la teneur en matière grasse du lait de bonne qualité physicochimique.
La méthode est applicable au lait cru de vache, de brebis et de chèvre, au lait allégé en matière grasse, au lait écrémé, au lait conservé chimiquement et au lait liquide ayant subi un traitement.
Elle n'est pas applicable lorsqu'une plus grande précision est demandée pour le lait écrémé, par exemple pour connaître l'efficacité de l'opération d'écrémage.

Mleko - Določevanje maščobe - Gravimetrijska metoda (Referenčna metoda) (ISO 1211:2010)

Ta mednarodni standard določa referenčno metodo za določevanje vsebnosti maščob mleka dobre fizikalno-kemične kvalitete. Ta metoda velja za surovo kravje mleko, surovo ovčje mleko, surovo kozje mleko, manj mastno mleko, posneto mleko, kemično ohranjeno mleko in predelano tekoče mleko. Ne uporablja se, kadar je potrebna visoka natančnost za posneto mleko, npr. da ugotovimo delovno učinkovitost ločevalnikov smetane.

General Information

• Status: Published
• Publication Date: 20-Jul-2010
• ICS: 67.100.10 - Milk and processed milk products
• Technical Committee: KŽP - Agricultural food products
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 08-Jun-2010
• Due Date: 13-Aug-2010
• Completion Date: 21-Jul-2010
• Ref Project: EN ISO 1211:2010 - Milk - Determination of fat content - Gravimetric method (Reference method) (ISO 1211:2010)

Relations

• Replaces: SIST EN ISO 1211:2001 - Milk - Determination of fat content - Gravimetric method (Reference method) (ISO 1211:1999)
• Effective Date: 01-Sep-2010
• Replaces: SIST EN ISO 1211:2001 - Milk - Determination of fat content - Gravimetric method (Reference method) (ISO 1211:1999)
• Effective Date: 08-Jun-2022

Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN ISO 1211:2010
01-september-2010
1DGRPHãþD
SIST EN ISO 1211:2001
0OHNR'RORþHYDQMHPDãþREH*UDYLPHWULMVNDPHWRGD5HIHUHQþQDPHWRGD,62

Milk - Determination of fat content - Gravimetric method (Reference method) (ISO
1211:2010)
Milch - Bestimmung des Fettgehaltes - Gravimetrisches Verfahren (Referenzverfahren)
(ISO 1211:2010)
Lait - Détermination de la teneur en matière grasse - Méthode gravimétrique (Méthode
de référence) (ISO 1211:2010)
Ta slovenski standard je istoveten z: EN ISO 1211:2010
ICS:
67.100.10 0OHNRLQSUHGHODQLPOHþQL Milk and processed milk
SURL]YRGL products
SIST EN ISO 1211:2010 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 1211:2010

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SIST EN ISO 1211:2010


EUROPEAN STANDARD
EN ISO 1211

NORME EUROPÉENNE

EUROPÄISCHE NORM
June 2010
ICS 67.100.10 Supersedes EN ISO 1211:2001
English Version
Milk - Determination of fat content - Gravimetric method
(Reference method) (ISO 1211:2010)
Lait - Détermination de la teneur en matière grasse - Milch - Bestimmung des Fettgehaltes - Gravimetrisches
Méthode gravimétrique (Méthode de référence) (ISO Verfahren (Referenzverfahren) (ISO 1211:2010)
1211:2010)
This European Standard was approved by CEN on 5 May 2010.

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, Croatia, 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
© 2010 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 1211:2010: E
worldwide for CEN national Members.

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SIST EN ISO 1211:2010
EN ISO 1211:2010 (E)
Contents Page
Foreword .3

2

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SIST EN ISO 1211:2010
EN ISO 1211:2010 (E)
Foreword
This document (EN ISO 1211:2010) has been prepared by Technical Committee ISO/TC 34 "Food products"
in collaboration with Technical Committee CEN/TC 302 “Milk and milk products - Methods of sampling and
analysis” the secretariat of which is held by NEN.
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 December 2010, and conflicting national standards shall be withdrawn
at the latest by December 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.
This document supersedes EN ISO 1211:2001.
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, Croatia, 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 1211:2010 has been approved by CEN as a EN ISO 1211:2010 without any modification.

3

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SIST EN ISO 1211:2010

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SIST EN ISO 1211:2010


INTERNATIONAL ISO
STANDARD 1211
IDF
1
Third edition
2010-06-01


Milk — Determination of fat content —
Gravimetric method (Reference method)
Lait — Détermination de la teneur en matière grasse — Méthode
gravimétrique (Méthode de référence)





Reference numbers
ISO 1211:2010(E)
IDF 1:2010(E)
©
ISO and IDF 2010

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SIST EN ISO 1211:2010
ISO 1211:2010(E)
IDF 1:2010(E)
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©  ISO and IDF 2010
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO or IDF at the respective
address below.
ISO copyright office International Dairy Federation
Case postale 56 • CH-1211 Geneva 20 Diamant Building • Boulevard Auguste Reyers 80 • B-1030 Brussels
Tel. + 41 22 749 01 11 Tel. + 32 2 733 98 88
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Published in Switzerland

ii © ISO and IDF 2010 – All rights reserved

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SIST EN ISO 1211:2010
ISO 1211:2010(E)
IDF 1:2010(E)
Contents Page
Foreword .iv
1 Scope.1
2 Normative references.1
3 Terms and definitions .1
4 Principle.1
5 Reagents.2
6 Apparatus.2
7 Sampling.3
8 Preparation of test sample .4
9 Procedure.4
9.1 General .4
9.2 Test portion.4
9.3 Blank tests .4
9.4 Preparation of fat-collecting vessel.5
9.5 Determination .5
10 Calculation and expression of results .7
10.1 Calculation .7
10.2 Expression of results.8
11 Precision.8
11.1 Interlaboratory test.8
11.2 Repeatability .8
11.3 Reproducibility .8
12 Test report.9
Annex A (informative) Notes on procedures.10
Annex B (informative) Alternative procedure using fat-extraction tubes with siphon or wash-bottle
fittings.12
Annex C (informative) Interlaboratory trial on raw milk.15
Annex D (informative) Interlaboratory trial on raw sheep milk and raw goat milk.17
Bibliography.18

© ISO and IDF 2010 – All rights reserved iii

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SIST EN ISO 1211:2010
ISO 1211:2010(E)
IDF 1:2010(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 1211⎪IDF 1 was prepared by Technical Committee ISO/TC 34, Food products, Subcommittee SC 5, Milk
and milk products, and the International Dairy Federation (IDF). It is being published jointly by ISO and IDF.
This third edition of ISO 1211⎪IDF 1 cancels and replaces the second edition (ISO 1211:1999), which has
been technically revised.
iv © ISO and IDF 2010 – All rights reserved

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SIST EN ISO 1211:2010
ISO 1211:2010(E)
IDF 1:2010(E)
Foreword
IDF (the International Dairy Federation) is a non-profit organization representing the dairy sector worldwide.
IDF membership comprises National Committees in every member country as well as regional dairy
associations having signed a formal agreement on cooperation with IDF. All members of IDF have the right to
be represented on the IDF Standing Committees carrying out the technical work. IDF collaborates with ISO in
the development of standard methods of analysis and sampling for milk and milk products.
The main task of Standing Committees is to prepare International Standards. Draft International Standards
adopted by the Standing Committees are circulated to the National Committees for endorsement prior to
publication as an International Standard. Publication as an International Standard requires approval by at least
50 % of the IDF National Committees casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. IDF shall not be held responsible for identifying any or all such patent rights.
ISO 1211⎪IDF 1 was prepared by the International Dairy Federation (IDF) and Technical Committee
ISO/TC 34, Food products, Subcommittee SC 5, Milk and milk products. It is being published jointly by IDF
and ISO.
All work was carried out by the Joint ISO-IDF Project Group on Fat in milk of the Standing Committee on
Analytical methods for composition under the aegis of its project leader, Mrs. S. Orlandini (IT).
This edition of ISO 1211⎪IDF 1 cancels and replaces IDF 1D:1996, which has been technically revised.

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SIST EN ISO 1211:2010

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SIST EN ISO 1211:2010
ISO 1211:2010(E)
INTERNATIONAL STANDARD
IDF 1:2010(E)

Milk — Determination of fat content — Gravimetric method
(Reference method)
WARNING — Persons using this International Standard should be familiar with normal laboratory
practice. This International Standard does not purport to address all of the safety problems, if any,
associated with its use. It is the responsibility of the user to establish appropriate safety and health
practices and to ensure compliance with any national regulatory conditions.
1 Scope
This International Standard specifies the reference method for the determination of the fat content of milk of
good physicochemical quality.
The method is applicable to raw cow milk, raw sheep milk, raw goat milk, reduced fat milk, skimmed milk,
chemically preserved milk, and processed liquid milk.
It is not applicable when greater accuracy is required for skimmed milk, e.g. to establish the operating
efficiency of cream separators.
[7]
NOTE ISO 7208 specifies a special method for skimmed milk products.
2 Normative references
The following referenced documents are indispensable for the application 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 3889⏐IDF 219, Milk and milk products — Specification of Mojonnier-type fat extraction flasks
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
fat content of milk
mass fraction of substances determined by the procedure specified in this International Standard
NOTE The fat content is expressed as a percentage mass fraction.
4 Principle
An ammoniacal ethanolic solution of a test sample is extracted with diethyl ether and light petroleum. The
solvents are removed by distillation or evaporation. The mass of the substances extracted is determined.
NOTE This is usually known as the Röse-Gottlieb principle.
© ISO and IDF 2010 – All rights reserved 1

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SIST EN ISO 1211:2010
ISO 1211:2010(E)
IDF 1:2010(E)
5 Reagents
Use only reagents of recognized analytical grade, unless otherwise specified, and distilled or demineralized
water or water of equivalent purity.
The reagents shall leave no appreciable residue when the determination is carried out by the method
specified (see 9.3.2).
5.1 Ammonia solution, containing a mass fraction of NH of approximately 25 % [ρ (NH ) = 910 g/l].
3 20 3
If an ammonia solution of this concentration is not available, a more concentrated solution of known
concentration may be used (see 9.5.1).
5.2 Ethanol (C H OH), or ethanol denatured by methanol, containing a volume fraction of ethanol of at
2 5
least 94 % (see A.4).
5.3 Congo red solution.
Dissolve 1 g of Congo red (C H N Na O S ) in water in a 100 ml one-mark volumetric flask (6.14). Make
32 22 6 2 6 2
up to the mark with water.
NOTE The use of this solution, which allows the interface between the solvent and aqueous layers to be seen more
clearly, is optional (see 9.5.2). Other aqueous colour solutions can be used provided that they do not affect the result of
the determination.
WARNING — Congo red is carcinogenic.
5.4 Diethyl ether (C H OC H ), free from peroxides (see A.3), and complying with the requirements for the
2 5 2 5
blank test (see 9.3.2 and A.2).
WARNING — The use of diethyl ether can lead to hazardous situations. Observe current safety
precautions for handling, use, and disposal.
5.5 Light petroleum, with any boiling range between 30 °C and 60 °C or, as equivalent, pentane
(CH [CH ] CH ) with a boiling point of 36 °C and complying with the requirements for the blank test (see 9.3.2,
3 2 3 3
A.1 and A.2).
5.6 Mixed solvent.
Shortly before use, mix equal volumes of diethyl ether (5.4) and light petroleum (5.5).
6 Apparatus
WARNING — Since the determination involves the use of volatile flammable solvents, all electrical
apparatus employed shall comply with legislation relating to the hazards in using such solvents.
Usual laboratory equipment and, in particular, the following.
6.1 Analytical balance, capable of weighing to the nearest 1 mg, with a readability of 0,1 mg.
6.2 Centrifuge, capable of holding the fat-extraction flasks or tubes (6.6) and capable of spinning at a
−1 −1
rotational frequency of 500 min to 600 min to produce a radial acceleration of 80g to 90g at the outer end
of the flasks or tubes.
The use of the centrifuge is optional, but recommended (see 9.5.5).
2 © ISO and IDF 2010 – All rights reserved

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SIST EN ISO 1211:2010
ISO 1211:2010(E)
IDF 1:2010(E)
6.3 Distillation or evaporation apparatus, suitable for distilling the solvents and ethanol from the boiling
or conical flasks, or evaporating from dishes (see 9.5.12) at a temperature not exceeding 100 °C.
6.4 Drying oven, electrically heated, with ventilation port(s) fully open, capable of operating at a
temperature of 102 °C ± 2 °C throughout its working space.
The oven shall be fitted with a suitable thermometer.
6.5 Water bath, capable of maintaining a temperature between 35 °C and 40 °C.
6.6 Mojonnier type fat-extraction flasks, as specified in ISO 3889⏐IDF 219.
NOTE It is also possible to use fat-extraction tubes, with siphon or wash-bottle fittings, but the procedure is then
different (see Annex B).
The fat-extraction flasks shall be provided with good quality cork bungs or stoppers of other material
[e.g. silicone rubber or polytetrafluoroethylene (PTFE)] unaffected by the reagents used. Cork bungs shall be
extracted with the diethyl ether (5.4), kept in water at a temperature of 60 °C or more for at least 15 min, and
shall then be allowed to cool in the water so that they are saturated when used.
6.7 Rack, suitable for holding the fat-extraction flasks (or tubes) (6.6).
6.8 Wash bottle, suitable for use with the mixed solvent (5.6).
A plastics wash bottle shall not be used.
6.9 Fat-collecting vessels, such as boiling flasks (flat-bottomed), of capacities 125 ml to 250 ml, conical
flasks, of capacity 250 ml, or metal dishes.
If metal dishes are used, they shall be of stainless steel, flat-bottomed with a diameter of 80 mm to 100 mm
and a height of approximately 50 mm.
6.10 Boiling aids, fat-free, of non-porous porcelain, silicon carbide or glass. Their use is optional.
[4]
6.11 Measuring cylinders, capacities 5 ml and 25 ml, ISO 4788 class A, or any other apparatus suitable
for the product concerned.
[2]
6.12 Pipettes, graduated, capacity 10 ml, ISO 835 class A.
6.13 Tongs, made of metal, suitable for holding flasks, beakers or dishes.
[3]
6.14 One-mark volumetric flask, capacity 100 ml, ISO 1042 class A.
7 Sampling
Sampling is not part of the method specified in this International Standard. A recommended sampling method
[1]
is given in ISO 707⏐IDF 50 .
It is important the laboratory receive a truly representative sample which has not been damaged or changed
during transport or storage.
Store laboratory samples at a temperature of between 2 °C and 6 °C from the time of sampling to the time of
commencing the procedure.
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SIST EN ISO 1211:2010
ISO 1211:2010(E)
IDF 1:2010(E)
8 Preparation of test sample
Using the water bath (6.5), warm the test sample to a temperature of 38 °C ± 2 °C. Gently mix the test sample
thoroughly without causing frothing or churning. Then cool the test sample quickly to 20 °C ± 2 °C.
If a homogeneous test sample can be obtained without pre-warming (e.g. for samples of skimmed milk), bring
the test sample to a temperature of 20 °C ± 2 °C and gently mix thoroughly by repeatedly inverting the sample
bottle.
A reliable value for the fat content cannot be expected:
a) if the milk is churned;
b) when a distinct smell of free fatty acids is perceptible;
NOTE Goat milk naturally contains a low level of free fatty acids, which are not completely extracted in this method.
c) if, during or after preparation of the test sample, white particles are visible on the walls of the sample
bottle or fat droplets float on the surface of the sample.
9 Procedure
9.1 General
If it is required to check whether the repeatability limit (11.2) is met, carry out two single determinations in
accordance with 9.2 to 9.5.
NOTE An alternative procedure using fat-extraction tubes with siphon or wash-bottle fittings (see Note to 6.6) is given
in Annex B.
9.2 Test portion
Mix the prepared test sample (Clause 8) by gently inverting the bottle three or four times. Immediately weigh,
to the nearest 1 mg, 10 g to 11 g of the test sample, directly or by difference, in a fat-extraction flask (6.6).
Transfer the test portion as completely as possible into the lower (small) bulb of the fat-extraction flask.
9.3 Blank tests
9.3.1 Blank test for method
Carry out a blank test simultaneously with the determination using the same procedure and same reagents,
but replacing the test portion in 9.2 by 10 ml of water (see A.1).
When a batch of test samples is analysed, the number of drying cycles may differ between different samples.
If one blank sample is used for the entire batch, ensure that the blank value, used in the calculation of the fat
content of any individual sample, was obtained under the same conditions as the individual test sample.
If the value obtained in the blank test regularly exceeds 1,0 mg, check the reagents if this has not been
recently done (9.3.2). Corrections of more than 2,5 mg should be mentioned in the test report.
9.3.2 Blank test for reagents
To test the quality of the reagents, carry out a blank test as specified in 9.3.1. Additionally use an empty fat-
collecting vessel, prepared as specified in 9.4, for mass control purposes. The reagents shall leave no residue
greater than 1,0 mg (see Clause A.2).
4 © ISO and IDF 2010 – All rights reserved

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SIST EN ISO 1211:2010
ISO 1211:2010(E)
IDF 1:2010(E)
If the residue of the complete reagent blank test is greater than 1,0 mg, determine the residue of the solvents
separately by distilling 100 ml of the diethyl ether (5.4) and light petroleum (5.5), respectively. Use an empty
fat-collecting vessel, prepared for control purposes as in the preceding paragraph, to obtain the real mass of
the residue which shall not exceed 1,0 mg.
Replace unsatisfactory reagents or solvents, or redistil solvents.
9.4 Preparation of fat-collecting vessel
Dry a fat-collecting vessel (6.9) with a few boiling aids (6.10) in the oven (6.4) maintained at 102 °C ± 2 °C for
1 h.
NOTE 1 Boiling aids are optional to promote gentle boiling during the subsequent removal of solvents, especially when
using glass fat-collecting vessels.
Protected from dust, allow the fat-collecting vessel to cool to the temperature of the weighing room. Cool a
glass fat-collecting vessel for at least 1 h and a metal dish for at least 30 min. To avoid insufficient cooling or
unduly long cooling times, do not cool the fat-collecting vessel in a desiccator.
Use tongs (6.13) to place the fat-collecting vessel on the balance. Weigh the fat-collecting vessel to the
nearest 1,0 mg.
NOTE 2 The use of tongs effectively avoids temperature variations.
9.5 Determination
9.5.1 Start the determination within 1 h of weighing the sample.
Add 2 ml of ammonia solution (5.1), or an equivalent volume of a more concentrated ammonia solution (see
5.1), to the test portion in the fat-extraction flask (9.2). Mix thoroughly with the test portion in the small bulb of
the fat-extraction flask.
9.5.2 Add 10 ml of ethanol (5.2). Mix gently but thoroughly by allowing the contents of the fat-extraction
flask to flow backwards and forwards between the small and large bulb. Avoid bringing the liquid too close to
the neck of the flask. If desired, add 2 drops of the Congo red solution (5.3).
9.5.3 Add 25 ml of diethyl ether (5.4). Close the fat-extraction flask with a cork bung saturated with water or
with a stopper of other material wetted with water (6.6). For 1 min, shake the flask vigorously, but not
excessively, to avoid the formation of persistent emulsions.
While shaking, keep the fat-extraction flask in a horizontal position with the small bulb extending upwards,
periodically allowing the liquid to run from the large bulb into the small bulb. Carefully remove the bung or
stopper and rinse it and the inside of the neck of the fat-extraction flask with a little mixed solvent (5.6). Use
the wash bottle (6.8) so that the rinsings run into the flask.
9.5.4 Add 25 ml of the light petroleum (5.5). Close the fat-extraction flask with the bung or stopper. Mix
again for 30 s as specified in 9.5.3.
9.5.5 Centrifuge the closed fat-extraction flask for between 1 min and 5 min at a radial acceleration of 80g
to 90g. If a centrifuge (6.2) is not available, allow the closed flask to stand in a rack (6.7) for at least 30 min
until the supernatant layer is clear and distinctly separated from the aqueous layer.
9.5.6 Carefully remove the cork or stopper and rinse it and the inside of the neck of the fat-extraction flask
with a little mixed solvent (5.6). Use the wash bottle (6.8) so that the rinsings run into the flask. If the interface
is below the bottom of the stem of the flask, raise it slightly above this level by gently adding water down the
side of the flask (see Figure 1) to facilitate the decantation of solvent.
NOTE In Figures 1 and 2, one of the three types of fat-extraction flask specified in ISO 3889⏐IDF 219 has been
chosen, but this does not imply any preference over the other types.
© ISO and IDF 2010 – All rights reserved 5

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SIST EN ISO 1211:2010
ISO 1211:2010(E)
IDF 1:2010(E)
9.5.7 Hold the fat-extraction flask by the small bulb and carefully decant as much as possible of the
supernatant layer (solvent Figure 1) into the prepared fat-collecting vessel (see 9.4). Avoid decantation of any
of the aqueous layer (see Figure 2).

Key
1 solvent
2 interface
3 aqueous layer
a
At second and third extraction.
b
At first extraction.
Figure 1 — Before decanting

Key
1 interface
2 aqueous layer
a
At second and third extraction.
b
At first extraction.
Figure 2 — After decanting
6 © ISO and IDF 2010 – All rights reserved

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SIST EN ISO 1211:2010
ISO 1211:2010(E)
IDF 1:2010(E)
9.5.8 Rinse the outside of the neck of the fat-extraction flask with a little mixed solvent (5.6). C
...