EN ISO 5764:2002

Milk - Determination of freezing point - Thermistor cryoscope method (Reference method) (ISO 5764:2002)

Milch - Bestimmung des Gefrierpunktes - Thermistor-Kryoskop-Verfahren (Referenzverfahren) (ISO 5764:2002)

Diese Internationale Norm legt ein Referenzverfahren zur Bestimmung des Gefrierpunktes von roher, pasteurisierter, ultrahocherhitzter (UHT) oder sterilisierter Vollmilch, teilentrahmter und entrahmter Milch (Magermilch) mit einem Thermistor-Kryoskop fest.
Der Gefrierpunkt kann zur Abschätzung des Anteils von Fremdwasser in Milch verwendet werden. Die Berechnung der Menge von Fremdwasser wird durch Tagesschwankungen, saisonale Schwankungen usw. erschwert und liegt nicht innerhalb des Anwendungsbereichs dieser Internationalen Norm.
Ergebnisse von Untersuchungsproben, deren titrierbare Acidität über 20 ml an 0,1 mol/l Natriumhydroxidlösung je 10 g fettfreier Trockenmasse beträgt, sind für die Milch im Originalzustand als nicht repräsentativ anzusehen.
ANMERKUNG   Sterilisation und Pasteurisierung im Vakuum können den Gefrierpunkt von Milch beeinflussen (siehe [6]).

Lait - Détermination du point de congélation - Méthode au cryoscope à thermistance (Méthode de référence) (ISO 5764:2002)

IEC 61076-8-100:2020 décrit les connecteurs blindés étanches à 2 pôles ou 3 pôles pour la transmission de puissance et à 2 pôles pour la transmission de données avec boîtier plastique (par la suite appelés connecteurs) pour équipements électriques et électroniques, et notamment leurs dimensions hors-tout, les dimensions des interfaces, les caractéristiques techniques, les exigences en matière de performances et les méthodes d’essai.
Le présent document s’applique à tous les connecteurs dont les exigences en matière d’étanchéité et de blindage répondent au présent document pour une tension assignée inférieure ou égale à 750 V en courant alternatif ou 1 000 V en courant continu avec un courant assigné de 20 A, pour des applications dans le domaine des équipements électriques et électroniques.

Mleko - Določevanje ledišča - Metoda Thermistor cryoscope (referenčna metoda) (ISO 5764:2002)

General Information

• Status: Withdrawn
• Publication Date: 14-May-2002
• Withdrawal Date: 05-May-2009
• ICS: 67.100.10 - Milk and processed milk products
• Technical Committee: CEN/TC 302 - Milk and milk products - Methods of sampling and analysis
• Drafting Committee: CEN/TC 302 - Milk and milk products - Methods of sampling and analysis
• Current Stage: 9960 - Withdrawal effective - Withdrawal
• Start Date: 06-May-2009
• Completion Date: 06-May-2009
• Ref Project: SIST EN ISO 5764:2002 - Milk - Determination of freezing point - Thermistor cryoscope method (Reference method) (ISO 5764:2002)

Relations

• Replaced By: EN ISO 5764:2009 - Milk - Determination of freezing point - Thermistor cryoscope method (Reference method) (ISO 5764:2009)
• Effective Date: 13-May-2009

Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN ISO 5764:2002
01-september-2002
0OHNR'RORþHYDQMHOHGLãþD0HWRGD7KHUPLVWRUFU\RVFRSHUHIHUHQþQDPHWRGD
,62
Milk - Determination of freezing point - Thermistor cryoscope method (Reference
method) (ISO 5764:2002)
Milch - Bestimmung des Gefrierpunktes - Thermistor-Kryoskop-Verfahren
(Referenzverfahren) (ISO 5764:2002)
Lait - Détermination du point de congélation - Méthode au cryoscope a thermistance
(Méthode de référence) (ISO 5764:2002)
Ta slovenski standard je istoveten z: EN ISO 5764:2002
ICS:
67.100.10 0OHNRLQSUHGHODQLPOHþQL Milk and processed milk
SURL]YRGL products
SIST EN ISO 5764:2002 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 5764:2002

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SIST EN ISO 5764:2002
EUROPEAN STANDARD
EN ISO 5764
NORME EUROPÉENNE
EUROPÄISCHE NORM
May 2002
ICS 67.100.10
English version
Milk - Determination of freezing point - Thermistor cryoscope
method (Reference method) (ISO 5764:2002)
Lait - Détermination du point de congélation - Méthode au Milch - Bestimmung des Gefrierpunktes - Thermistor-
cryoscope à thermistance (Méthode de référence) (ISO Kryoskop-Verfahren (Referenzverfahren) (ISO 5764:2002)
5764:2002)
This European Standard was approved by CEN on 4 May 2002.
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 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 Management Centre has the same status as the official
versions.
CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece,
Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2002 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 5764:2002 E
worldwide for CEN national Members.

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SIST EN ISO 5764:2002
EN ISO 5764:2002 (E)
CORRECTED  2002-06-19
Foreword
This document (EN ISO 5764:2002) has been prepared by Technical Committee ISO/TC 34
"Agricultural 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 November 2002, and conflicting
national standards shall be withdrawn at the latest by November 2002.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of
the following countries are bound to implement this European Standard: Austria, Belgium,
Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy,
Luxembourg, Malta, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the
United Kingdom.
Endorsement notice
The text of the International Standard ISO 5764:2002 has been approved by CEN as a
European Standard without any modifications.
NOTE Normative references to International Standards are listed in annex ZA (normative).
2

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SIST EN ISO 5764:2002
prEN ISO 5764:2002 (E)
Annex ZA
(normative)
Normative references to international publications
with their relevant European publications
This European Standard incorporates by dated or undated reference, provisions from other
publications. These normative references are cited at the appropriate places in the text and the
publications are listed hereafter. For dated references, subsequent amendments to or revisions
of any of these publications apply to this European Standard only when incorporated in it by
amendment or revision. For undated references the latest edition of the publication referred to
applies (including amendments).
NOTE Where an International Publication has been modified by common modifications,
indicated by (mod.), the relevant EN/HD applies.
Publication Year Title EN Year
ISO 1042 1998 Laboratory glassware — One mark EN ISO 1042 1999
volumetric flasks
ISO 3696 1987 Water for analytical laboratory EN ISO 3696 1995
use — Specification and test
methods
3

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SIST EN ISO 5764:2002

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SIST EN ISO 5764:2002



INTERNATIONAL ISO
STANDARD 5764
IDF
108
Second edition
2002-05-15


Milk — Determination of freezing point —
Thermistor cryoscope method (Reference
method)
Lait — Détermination du point de congélation — Méthode au cryoscope à
thermistance (Méthode de référence)




Reference numbers
ISO 5764:2002(E)
IDF 108:2002(E)
©
 ISO and IDF 2002

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SIST EN ISO 5764:2002
ISO 5764:2002(E)
IDF 108:2002(E)
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©  ISO and IDF 2002
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
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Tel. + 41 22 749 01 11 Tel. + 32 2 733 98 88
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Printed in Switzerland

ii © ISO and IDF 2002 – All rights reserved

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SIST EN ISO 5764:2002
ISO 5764:2002(E)
IDF 108:2002(E)
Contents Page
Foreword.iv
Introduction.vi
1 Scope .1
2 Normative references.1
3 Term and definition .1
4 Principle.1
5 Reagents.2
6 Apparatus .3
7 Sampling.5
8 Calibration of the thermistor cryoscope .5
9 Preparation of test sample.5
9.1 Preparation.5
9.2 Sample condition.5
10 Procedure .6
10.1 Preliminary checks.6
10.2 Routine calibration check.6
10.3 Determination.6
11 Calculation and expression of results.6
11.1 Calculation .6
11.2 Expression of results .7
12 Precision.7
12.1 Interlaboratory test.7
12.2 Repeatability .7
12.3 Reproducibility.7
13 Test report .7
Annex A (informative) Results of the interlaboratory test .8
Annex B (informative) Guidelines for the application of routine thermistor cryoscope methods .10
Annex C (informative) Adjustment of the freezing point value used as the reference for genuine milk .14
Bibliography.15

© ISO and IDF 2002 – All rights reserved iii

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SIST EN ISO 5764:2002
ISO 5764:2002(E)
IDF 108:2002(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 3.
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 International Standard may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights.
International Standard ISO 5764|IDF 108 was prepared by Technical Committee ISO/TC 34, Food products,
Subcommittee SC 5, Milk and milk products, and the International Dairy Federation (IDF), in collaboration with
AOAC International. It is being published jointly by ISO and IDF and separately by AOAC International.
This joint edition of ISO 5764|IDF 108 cancels and replaces the first edition of ISO 5764:1987, which has been
technically revised.
Annexes A to C of this International Standard are for information only.
iv © ISO and IDF 2002 – All rights reserved

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SIST EN ISO 5764:2002
ISO 5764:2002(E)
IDF 108:2002(E)
Foreword
IDF (the International Dairy Federation) is a worldwide federation of the dairy sector with a National Committee in
every member country. Every National Committee has the right to be represented on the IDF Standing Committees
carrying out the technical work. IDF collaborates with ISO and AOAC International in the development of standard
methods of analysis and sampling for milk and milk products.
Draft International Standards adopted by the Action Teams and Standing Committees are circulated to the National
Committees for voting. Publication as an International Standard requires approval by at least 50 % of National
Committees casting a vote.
International Standard ISO 5764|IDF 108 was prepared by Technical Committee ISO/TC 34, Food products,
Subcommittee SC 5, Milk and milk products, and the International Dairy Federation (IDF), in collaboration with
AOAC International. It is being published jointly by ISO and IDF and separately by AOAC International.
All work was carried out by the Joint ISO/IDF/AOAC Action Team, Water, of the Standing Committee on Main
components of milk, under the aegis of its project leader, Mr H.J.C.M. van den Bijgaart (NL).
This joint edition of ISO 5764|IDF 108 cancels and replaces the second edition of IDF 108:1991, which has been
technically revised.
© ISO and IDF 2002 – All rights reserved v

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SIST EN ISO 5764:2002
ISO 5764:2002(E)
IDF 108:2002(E)
Introduction
The method described in this International Standard for the determination of the freezing point of milk uses a
thermistor cryoscope, in which a thermostatically controlled device is cooled and a thermistor probe is used for the
measurement of the freezing point.
This reference method requires the use of plateau-timed instruments. For routine measurements, other thermistor
cryoscope methods, i.e. fixed time procedures, can be used. Guidelines for the application of other procedures are
given in annex B.

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SIST EN ISO 5764:2002
ISO 5764:2002(E)
INTERNATIONAL STANDARD
IDF 108:2002(E)

Milk — Determination of freezing point — Thermistor cryoscope
method (Reference method)
1 Scope
This International Standard specifies a reference method for the determination of the freezing point of raw,
pasteurized, UHT-treated or sterilized whole milk, partially skimmed milk and skimmed milk by using a thermistor
cryoscope.
The freezing point can be used for estimating the proportion of extraneous water in milk. Calculation of the amount
of extraneous water is complicated by daily variation, seasonal variation, etc. and is not within the scope of this
International Standard.
Results obtained from samples with a titratable acidity exceeding 20 ml of 0,1 mol/l sodium hydroxide solution per
10 g of non-fat solids will not be representative of the original milk.
NOTE Sterilization and vacuum pasteurization can affect the freezing point of milk (see reference [6]).
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of
this International Standard. For dated references, subsequent amendments to, or revisions of, any of these
publications do not apply. However, parties to agreements based on this International Standard are encouraged to
investigate the possibility of applying the most recent editions of the normative documents indicated below. For
undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC
maintain registers of currently valid International Standards.
ISO 1042, Laboratory glassware — One-mark volumetric flasks
ISO 3696, Water for analytical laboratory use — Specification and test methods
ISO 6091, Dried milk — Determination of titratable acidity (Reference method)
3 Term and definition
For the purposes of this International Standard, the following term and definition applies.
3.1
freezing point of milk
value obtained using the method specified in this International Standard
NOTE The freezing point is expressed in millidegrees Celsius (m°C).
4 Principle
A test sample of milk is super-cooled to an appropriate temperature and crystallization is induced by means
sufficient to cause an instantaneous release of heat with an accompanying warming of the sample to a temperature
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SIST EN ISO 5764:2002
ISO 5764:2002(E)
IDF 108:2002(E)
plateau. The plateau is reached when the temperature rise has not exceeded 0,5 m°C over the last 20 s. The thus-
attained temperature corresponds to the freezing point of the milk sample.
The instrument is calibrated by adjusting it to give the correct readings for two sodium chloride standard solutions,
using the same procedure as for test portions of milk.
5 Reagents
Use only reagents of recognized analytical grade, unless otherwise specified.
5.1 Water, complying with grade 2 in accordance with ISO 3696, or water of equivalent quality distilled from
borosilicate glass apparatus.
The water shall be boiled and cooled to 20 °C ± 2 °C shortly before use.
5.2 Sodium chloride (NaCl), finely ground, dried in the electric furnace (6.7) at 300 °C ± 25 °C for 5 h or
alternatively dried in the drying oven (6.8) at 130 °C ± 2 °C for at least 24 h, then cooled to room temperature in a
desiccator (6.9).
5.3 Sodium chloride standard solutions
Weigh, to the nearest 0,1 mg, the appropriate amount (see Table 1) of prepared dry sodium chloride (5.2) in a
weighing bottle (6.5). Dissolve in water (5.1) and transfer quantitatively to a 1 000 ml one-mark volumetric flask
(6.6). Dilute to the 1 000 ml mark with water (5.1) at 20 °C ± 2 °C and mix.
Alternatively and preferably, make up the sodium chloride standard solution on a gram per kilogram basis (see
Table 1, second column) by weighing the required amount of prepared dry sodium chloride (5.2) to the nearest
0,1 mg and dissolving it in exactly 1 kg of water (5.1). Store standard solutions at about 5 °C in well-stoppered
polyethylene bottles (6.10) of capacity not greater than 250 ml.
Before using a standard solution, gently invert and rotate the bottle several times to mix its contents thoroughly. At
no time should the standard solution be agitated violently, as this can lead to incorporation of air. Pour samples of
standard solutions from the bottles. Never use pipettes for this purpose. Do not use standard solutions from bottles
less than one-quarter full, or more than 2 months old, or containing visible moulds.
Table 1 — Freezing point of sodium chloride standard solutions
NaCl solution at 20 °C NaCl solution Freezing point
g/l solution g/kg water m°C
6,731 6,763
− 400,0
6,868 6,901 − 408,0
7,587 7,625 − 450,0
8,444 8,489 − 500,0
8,615 8,662
− 510,0
8,650 8,697
− 512,0
8,787 8,835 − 520,0
8,959 9,008 − 530,0
9,130 9,181
− 540,0
9,302 9,354
− 550,0
9,422 9,475 − 557,0
10,161 10,220 − 600,0
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SIST EN ISO 5764:2002
ISO 5764:2002(E)
IDF 108:2002(E)
For this reference method, only unpreserved sodium chloride standard solutions should be used. For routine
methods, sodium chloride standard solutions with a fungicidal or fungistatic agent may be used. For guidance, see
annex B.
6 Apparatus
Usual laboratory apparatus and, in particular, the following.
6.1 Cryoscope, consisting of a thermostatically controlled cooling device, a thermistor probe with associated
circuit, a read-out device, a sample agitator and a crystallization device (see Figure 1).
6.1.1 Cooling device
Several types of thermostated cooling devices may be used. The following types are given as examples:
 immersion type: a cooling bath with a suitable buffer capacity;
 circulation type: a continuous stream of cooling liquid around the sample tube;
 cooling block type: a cooling block with a small amount of cooling liquid.
After the initiation of freezing, keep the temperature of the cooling liquid around the sample tube constant at
− 7,0 °C ± 0,5 °C.
NOTE A suitable cooling liquid is a 33 % (volume fraction) aqueous solution of propylene glycol.
6.1.2 Measuring device, associated circuitry and read-out device
The thermistor shall be of the glass-probe type with diameter of 1,60 mm ± 0,4 mm and an electrical resistance of
between 3 Ω and 30 kΩ at 0 °C.
The type and dimensions of the shank material (including a possible filler) shall not allow a heat transfer into the
−3
sample greater than 2,5 × 10 J/s, under operating conditions.
When the probe is in the measurement position, the thermistor bead shall lie on the axis of the sample and at equal
distances from the inner walls and the inner bottom of the tube (see Figure 1).
The thermistor and the associated circuitry shall show a discrimination of 1 m°C or better over a range of −400 m°C
to −600 m°C.
The linearity of the circuit shall be such that no error greater than 1 m°C is introduced at any point within the range
of −400 m°C to −600 m°C when the instrument is correctly operated.
The read-out device shall provide a discrimination of 1 m°C or better over a range of at least 0 m°C to −1 000 m°C.
6.1.3 Stirring wire, inert to milk, used to stir the test portion during cooling.
The stirring wire shall be adjustable for amplitude and be mounted vertically in accordance with the manufacturer's
instruction. The wire shall vibrate laterally with an amplitude of 2 mm to 3 mm to ensure that the temperature within
the test portion remains uniform during cooling. At no time during its normal stirring operation shall the wire strike
the glass probe or the wall of the tube.
6.1.4 Device for initiating freezing: any device that, when operated, instantaneously initiates freezing of the
test portion when reaching −3,0 °C.
The stirring wire (6.1.3) may be used for this purpose. One method is to increase the amplitude of vibration for 1 s
to 2 s such that the stirring wire strikes the wall of the sample tube (6.2).
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SIST EN ISO 5764:2002
ISO 5764:2002(E)
IDF 108:2002(E)
Dimensions in millimetres

Key
1 Mandrel 3 Stirring wire
2 Sample tube 4 Thermistor bead
Figure 1 — Detail of thermistor cryoscope
6.2 Sample tubes, symmetrical, made of borosilicate glass, of length 50,5 mm ± 0,2 mm, external diameter
16,0 mm ± 0,2 mm, and internal diameter 13,7 mm ± 0,3 mm (see Figure 1).
The wall thickness throughout the tube shall not vary by more than 0,1 mm.
The tubes shall be equally shaped so that equal freezing points are obtained for equal volumes of the same
solution. Check on equality before using the tubes.
6.3 Main power supply, capable of operating within the manufacturer's specifications.
6.4 Analytical balance, capable of weighing to the nearest 0,1 mg.
6.5 Weighing bottle
6.6 One-mark volumetric flasks, of capacity 1 000 ml, complying with the requirements of ISO 1042, class A.
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SIST EN ISO 5764:2002
ISO 5764:2002(E)
IDF 108:2002(E)
6.7 Electric furnace, capable of being controlled at 300 °C ± 25 °C.
6.8 Drying oven, capable of being controlled at 130 °C ± 2 °C.
6.9 Desiccator
6.10 Polyethylene bottles, of maximum capacity 250 ml, with a suitable stopper.
7 Sampling
Sampling is not part of the method specified in this International Standard. A recommended sampling method is
given in ISO 707.
It is important that the laboratory receive a sample that is truly representative and has not been damaged or
changed during transport or storage.
If necessary, the test samples may be stored at a temperature of between 0 °C and 6 °C.
It is preferable to test the samples immediately upon arrival at the laboratory.
8 Calibration of the thermistor cryoscope
Ensure that the cryoscope (6.1) is in working condition in accordance with the manufacturer's instructions. Check
the position of the probe, the amplitude of vibration of the stirring wire and the temperature of the cooling device
(6.1.1).
Select two sodium chloride standard solutions (see Table 1) which closely bracket the expected value of the
freezing point of the milk to be tested. The difference in the freezing points between the two selected sodium
chloride standard solutions shall not be less than 100 m°C. Take care that the temperatures of the selected sodium
chloride standard solutions and that of the test sample are similar.
Pour 2,5 ml ± 0,1 ml of the sodium chloride standard solutions into clean, dry sample tubes (6.2) and calibrate the
instrument as indicated by the manufacturer. Use sample tubes (6.2) of the same type as those being used during
testing of the sample. Thereafter, the thermistor cryoscope is ready for use.
9 Preparation of test sample
9.1 Preparation
If necessary, remove any visible foreign bodies or solid butterfat from the test sample by filtering into a clean dry
vessel. Mix the sample gently. Use a filter that is inert to milk and effective when used at laboratory temperature.
Test the samples at their storage temperature or after having reached the laboratory temperature before
commencing the determination. However, the test samples and the sodium chloride standard solutions should have
the same temperature when commencing the determination (see also clause 8).
9.2 Sample condition
If doubts exist about the sample condition, determine the titratable acidity of the test sample by the method
specified in ISO 6091 as far as possible at the same time as determining the freezing point.
Results obtained from test samples with a titratable acidity exceeding 20 ml of 0,1 mol/l sodium hydroxide solution
per 10 g of non-fat solids will not be representative of the original milk.
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SIST EN ISO 5764:2002
ISO 5764:2002(E)
IDF 108:2002(E)
10 Procedure
10.1 Preliminary checks
Carry out preliminary instrument checks in accordance with the manufacturers' instructions.
10.2 Routine calibration check
Before each series of determinations, measure the freezing point of a sodium chloride standard solution (5.3) (e.g.
a solution with a freezing point of −512 m°C) until the values obtained in two consecutive determinations do not
differ by more than 1 m°C.
If the arithmetic mean of the two results differs from the freezing point of the sodium chloride standard solution
used by more than 2 m°C, recalibrate the cryoscope as described in clause 8.
If the cryoscope is in continuous use, carry out a routine calibration check at least once every hour.
10.3 Determination
Gently invert and rotate the sample container several times to mix its contents, thereby avoiding the incorporation
of air.
Use a pipette to transfer a test portion of 2,5 ml ± 0,1 ml of the prepared test sample (9.1) into a clean and dry
sample tube (6.2). Ensure that the probe and the stirring wire (6.1.3) are clean and dry. If necessary, wipe carefully
with a soft, clean and lint-less tissue.
Insert the sample tube into the calibrated cryoscope (6.1) according to the manufacturer's instructions. Start the
instrument to cool the test portion and initiate freezing at −3,0 °C ± 0,1 °C.
The plateau is reached when the temperature rise over the last 20 s has not exceeded 0,5 m°C. For instruments with
a resolution not better than 1 m°C, the plateau is reached as soon as the temperature
...