Commission Regulation (EC) No 355/2005 of 28 February 2005 amending Regulation (EEC) No 2676/90 determining Community methods for the analysis of wines
Date: 2005-02-28
Institutions: European Commission
Subjects: alcohol, analytical chemistry, fruit product, product quality, wine

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COMMISSION REGULATION (EC) No 355/2005

of 28 February 2005

amending Regulation (EEC) No 2676/90 determining Community methods for the analysis of wines

THE COMMISSION OF THE EUROPEAN COMMUNITIES,

Having regard to the Treaty
Community,

establishing the European

Having regard to Council Regulation (EC) No 1493/1999 of 17
May 1999 on the common organisation of
in
wine (1), and in particular Article 46(3) thereof,

the market

(4)

(5)

Whereas:

this method and the experimental values for the vali-
dation parameters
the method should also be
included in Chapter 3 of the Annex to that Regulation.

for

Regulation (EEC) No 2676/90 should therefore be
amended accordingly.

The measures provided for in this Regulation are in
the Management
accordance with the opinion of
Committee for Wine,

(1)

(2)

(3)

electronic

densimetry

The method for measuring the alcoholic strength of wine
in
by
accordance with internationally recognised criteria. The
International Vine and Wine Office (OIV) adopted the
new description of this method at its General Assembly
in 2000.

validated

been

has

Use of this measurement method can constitute a simpler
and more accurate means of checking the alcoholic
strength by volume of wines.

There is no longer any need to recognise the equivalence
of this method with the methods described in Chapter 3
to Commission Regulation (EEC)
of
No 2676/90 (2), and Article 3(2) of
that Regulation
should therefore be deleted. The updated description of

the Annex

HAS ADOPTED THIS REGULATION:

Article 1

Regulation (EEC) No 2676/90 is hereby amended as follows:

1. Article 3(2) is deleted.

2. The Annex is amended in accordance with the Annex hereto.

Article 2

This Regulation shall enter into force on the seventh day
following its publication in the Official Journal of the European
Union.

This Regulation shall be binding in its entirety and directly applicable in all Member States.

Done at Brussels, 28 February 2005.

For the Commission

Mariann FISCHER BOEL
Member of the Commission

(1) OJ L 179, 14.7.1999, p. 1. Regulation as amended by the 2003 Act

of Accession.

(2) OJ L 272, 3.10.1990, p. 1. Regulation as last amended by Regu-

lation (EC) No 128/2004 (OJ L 19, 27.1.2004, p. 3).

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Chapter 3 of the Annex to Regulation (EEC) No 2676/90, ‘Alcoholic strength by volume’, is hereby amended as follows:

ANNEX

1. point 2.2 is replaced by the following:

‘2.2.

Reference methods:

— measurement of the alcoholic strength of the distillate using a pycnometer,

— measurement of the alcoholic strength of wines using a hydrostatic balance,

— measurement of the alcoholic strength of wines by electronic densimetry using a frequency oscillator.’;

2.

in point 4, the title is replaced by the following title and subtitle:

REFERENCE METHODS

‘4.
4–A Measurement of the alcoholic strength of the distillate using a pycnometer’;

3.

in paragraph 4a, the title is replaced by the following:

‘4–B Measurement of the alcoholic strength of wines using a hydrostatic balance’;

4. the following paragraph 4–C is inserted after paragraph 4–B:

‘4–C Measurement of the alcoholic strength of wines by electronic densimetry using a frequency oscillator

1.

Method of measurement

1.1.

Title and introduction

The alcoholic strength by volume of wines must be measured before marketing, principally to comply
with labelling rules.

Alcoholic strength by volume is defined in paragraph 1 of this chapter.

1.2.

Purpose and scope

The method of measurement described is electronic densimetry using a frequency oscillator.

For the purposes of the regulatory provisions in force, the trial temperature is set at 20 °C.

1.3.

Principle and definitions

The principle of this method is based on distilling wine volume by volume. The distilling method is
described in paragraph 3 of this Chapter. Distillation eliminates non-volatile substances. Homologues of
ethanol, together with ethanol and ethanol homologues in ethyl esters, are included in the alcoholic
strength since they occur in the distillate.

The density of the distillate obtained is then measured. The density of a liquid at a given temperature
is equal to the quotient of the mass over its volume:

ρ = m/V, for wine, it is expressed in g/ml.

For a hydroalcoholic solution such as a distillate, where the temperature is known, tables can be used to
map density and alcoholic strength. This alcoholic strength corresponds to that of wine (distillation
volume by volume).

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In this method the density of the distillate is measured by electronic densimetry using a frequency
oscillator. The principle consists of measuring the period of oscillation of a tube containing the sample
subject to electromagnetic excitation. The density can then be calculated – it is linked to the period of
oscillation by the following formula:

ρ ¼ T2 (cid:1)

8
: C

4π2V

9
; (cid:2)

9
;

8
: M
V

(1)

ρ= density of the sample
T= period of vibration induced
M= mass of the empty tube
C= spring constant
V= volume of the sample in vibration

This link takes the form ρ = A T2 – B (2); hence there is a linear relationship between the density and
the period squared. The constants A and B are specific to each oscillator and are estimated by measuring
the period of fluids of known density.

1.4.

Reagents and products

1.4.1. R e f e r e n c e f l u i d s

Two reference fluids are used to adjust the densimeter. The densities of the reference fluids must
encompass those of the distillates to be measured. A difference in the density of the reference fluids
greater than 0,01000 g/ml is recommended. Their density must be known with a degree of uncertainty
below +/- 0,00005 g/ml, at a temperature of 20,00 °C +/- 0,05 °C.

To measure the alcoholic strength by volume using an electronic densimeter, the reference fluids are:

— dry air (unpolluted),

— water of at least grade 3 as defined by ISO 3696:1987 should be used,

— hydroalcoholic solutions of reference density,

— solutions linked to national viscosity standards below 2 mm2/s.

1.4.2. C l e a n i n g a n d d r y i n g p r o d u c t s

— detergents, acids,

— organic solvents: ethanol 96 % vol., pure acetone.

1.5. Apparatus

1.5.1. E l e c t r o n i c d e n s i m e t e r u s i n g a f r e q u e n c y o s c i l l a t o r

The electronic densimeter comprises the following:

— a measuring cell with a measuring tube and thermostatic chamber,

— a system for making the tube oscillate and for measuring the period of oscillation,

— a clock,

— a digital display unit, and possibly a calculator.

The densimeter is placed on a perfectly stable stand that is insulated from all vibrations.

1.5.2. C o n t r o l l i n g t h e t e m p e r a t u r e i n t h e m e a s u r i n g c e l l

The measuring tube is placed in a thermostatic chamber. The temperature stability must be +/- 0,02 °C
or better.

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Where possible, the temperature of the measuring cell should be checked as this has a strong impact on
the measurement results. The density of a hydroalcoholic solution of 10 % vol is 0,98471 g/ml at 20 °C
and 0,98447 g/ml at 21 °C, or a difference of 0,00024 g/ml.

The trial temperature is set at 20 °C. The temperature is measured in the cell using a thermometer with a
resolution of below 0,01 °C in line with national standards.
It should guarantee a temperature
measurement with under +/- 0,07 °C uncertainty.

1.5.3. C a l i b r a t i o n o f

t h e a p p a r a t u s

The apparatus must be calibrated before its first use, then every six months or if the check is unsa-
tisfactory. Two reference fluids should be used to calculate the constants A and B (see above formula 2).
Calibration should be carried out in line with the operating instructions for the apparatus. In principle,
calibration is carried out using dry air (taking into account atmospheric pressure) and extremely pure
water (twice distilled and/or micro-filtered with extremely high resistivity > 18 MΩ).

1.5.4. C h e c k i n g t h e c a l i b r a t i o n

To check the calibration, measure the density of the reference fluids.

The air density should be checked every day. A difference between the theoretical and the actual density
greater than 0,00008 g/ml may indicate that the tube is blocked. It should therefore be cleaned. After
cleaning, check the air density once again. If this check is not conclusive, the apparatus must be adjusted.

Check the water density also. If the difference between the theoretical and the actual density is greater
than 0,00008 g/ml, the apparatus should be adjusted.

If it is difficult to check the temperature of the cell, the density of a hydroalcoholic solution with an
alcoholic strength by volume comparable to that of the distillates analysed can be checked directly.

1.5.5. C h e c k s

If the difference between the theoretical density of a reference solution (known with under 0,00005 g/ml
uncertainty) and the measurement is greater than 0,00008 g/ml, the temperature of the cell must be
checked.

1.6.

Sampling and preparation of the samples
(see point 3 of this Chapter, “Method of obtaining distillate”).

1.7.

Procedure

After obtaining the distillate, measure its density or alcoholic strength by volume using densimetry.

First ensure the temperature stability of the measuring cell. The distillate in the densimeter cell must not
contain air bubbles and must be homogeneous. If a lighting system is available which can help verify the
absence of bubbles, it should quickly be switched off after carrying out the checks as the heat generated
by the bulb affects the measuring temperature.

If the apparatus only gives the period, the density should be calculated using the constants A and B (see
1.3). If the apparatus does not give the alcoholic strength by volume directly, this can be obtained from
the tables.

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1.8.

Expression of results
The alcoholic strength by volume of the wine is that obtained for the distillate. It is expressed in “% vol”.

If the temperature conditions cannot be complied with, correct the result to express it at 20 °C. Give the
result to two decimal places.

1.9.

Remarks

The volume placed in the measuring cell must be large enough to avoid any contamination by the
previous sample. Consequently, at least two measurements should be carried out. If these do not give
results within the repeatability limit, a third measurement
is needed. The results of the last two
measurements are normally homogeneous and the first value is eliminated.

1.10. Precision

For samples with an alcoholic strength by volume of between 4 and 18 % vol

Repeatability (r)

Reproducibility (R)

=

=

0,067 (% vol)

0,0454 + 0,0105 × alcoholic
strength by volume

2.

Interlaboratory trials. Precision and accuracy on adjuncts

The method performance characteristics shown in paragraph 1.10 were obtained from an interlaboratory
test carried out in accordance with established international procedures on six samples and by eleven
laboratories.

All the details and repeatability and reproducibility calculations carried out in this test are described in
the Chapter “TITRE ALCOOMETRIQUE VOLUMIQUE” (Alcoholic strength by volume) (point 4.B.2) of
the OIV’s “Recueil International des Méthodes d’Analyse” (compendium of analysis methods – 2004 edition).’