Commission Regulation (EC) No 2870/2000 of 19 December 2000 laying down Community reference methods for the analysis of spirits drinks

Article 1

The Community reference methods for the analysis of spirits drinks to ensure compliance with Regulation (EEC) No 1576/89 and Regulation (EEC) No 1014/90:

— when any official control takes place, or

— in the event of a dispute,

shall be those set out in the Annex hereto.

Article 1a

However, where the alcohol sample is not clear or suspended particles are visible, the sample shall be distilled.

Article 2

Notwithstanding the first indent of Article 1, other analytical methods shall be permitted, under the responsibility of the director of the laboratory, on condition that the accuracy and precision (repeatability and reproducibility) of the methods are at least equivalent to those of the relevant reference analytical methods given in the Annex.

Article 3

Where Community analytical reference methods are not laid down for the detection and quantification of substances contained in a particular spirit drink, the following methods shall be used:

(a) analytical methods which are validated to internationally recognised procedures and in particular meet the criteria set in the Annex to Directive 85/591/EEC;

(b) analytical methods conforming to the recommended standards of the International Organisation for Standardisation (ISO);

(c) analytical methods recognised by the General Assembly of the International Vine and Wine Office (OIV) and published by that Office;

(d) in the absence of a method as indicated at (a), (b) or (c), by reason of its accuracy, repeatability and reproducibility: — an analytical method approved by the Member State concerned, — where necessary, any other suitable analytical method.

Article 4

For the purposes of this Regulation:

(a) ‘repeatability limit’: shall be the value less than or equal to which the absolute difference between two test results obtained under the repeatability conditions (same operator, same apparatus, same laboratory and a short interval of time) may be expected to be with a probability of 95 % {ISO 3534-1};

(b) ‘reproducibility limit’: shall be the value less than or equal to which the absolute difference between two test results obtained under the reproducibility conditions (different operators, different apparatus and different laboratories), may be expected to be with a probability of 95 % {ISO 3534-1};

(c) ‘accuracy’: shall be the closeness of agreement between a test result and the accepted reference value {ISO 3534-1}.

Article 5

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

It shall apply from 1 January 2001.

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

ANNEX

I. DETERMINATION OF ALCOHOLIC STRENGTH BY VOLUME OF SPIRIT DRINKS

Introduction

The reference method includes two Appendices:

Appendix I : Preparation of distillate

Appendix II : Measurement of density of distillate

The method is suitable for the determination of the real alcoholic strength by volume of spirit drinks.

ISO 3696:1987: Water for analytical laboratory use — Specifications and test methods.

3.1. Reference temperature: The reference temperature for the determination of alcoholic strength by volume, density and specific gravity of spirit drinks is 20 °C. Note 1: The term ‘at t °C’ is reserved for all determinations (of density or alcoholic strength by volume) expressed at a temperature other than the reference temperature of 20 °C.

3.2. Density: The density is the mass per unit volume in vacuo of spirit drinks at 20 °C. It is expressed in kilograms per cubic metre and its symbol is ρ20 °C or ρ20.

3.3. Specific gravity: The specific gravity is the ratio, expressed as a decimal number, of the density of spirit drinks at 20 °C to the density of water at the same temperature. It is denoted by the symbol d20 °C/20 °C or d20/20, or simply d when there is no possibility of confusion. The characteristic that was measured must be specified on the assay certificate using the above-defined symbols only. Note 2: It is possible to obtain the specific gravity from the density ρ20 at 20 °C:

or

where 998,203 is the density of water at 20 °C.

3.4. Real alcoholic strength by volume:

The real alcoholic strength by volume of spirit drinks is equal to the number of litres of ethyl alcohol contained in 100 l of a water-alcohol mixture having the same density as the alcohol or spirit after distillation. The reference values for alcoholic strength by volume (% vol) at 20 °C versus density at 20 °C for different water-alcohol mixtures that are to be used are those given in the international table adopted by the International Legal Metrology Organisation in its Recommendation No 22. The general equation relating the alcoholic strength by volume and density of a water-alcohol mixture at a given temperature is given on page 40 in Chapter 3 ‘Alcoholic strength by volume’ of the Annex to Commission Regulation (EEC) No 2676/90 (OJ L 272, 3.10.1990, p. 1) or in the manual of analysis methods of the OIV (1994) (p. 17). Note 3: For liqueurs and crèmes for which it is very difficult to measure volume accurately the sample must be weighed and the alcoholic strength is calculated first by mass. Conversion formula: where ASM = alcoholic strength by mass, ρ20 (alcohol) = 789,24 kg/m³

Following distillation, the alcoholic strength by volume of the distillate is determined by pycnometry, electronic densimetry, or densimetry using a hydrostatic balance.

APPENDIX I: PREPARATION OF DISTILLATE

The method is suitable for the preparation of distillates to be used to determine the real alcoholic strength by volume of spirit drinks.

The spirits are distilled to separate the ethyl alcohol and other volatile compounds from the extractive matter (substances which do not distil).

3.1.Anti-bumping granules.

3.2.Concentrated antifoam emulsion (for crème liqueurs).

Usual laboratory apparatus and in particular the following.

4.1. Water bath capable of being maintained at 10 °C to 15 °C. Water bath capable of being maintained at 20 °C (± 0,2 °C).

4.2. Class A volumetric flasks, 100 ml and 200 ml, that have been certified to 0,1 % and 0,15 % respectively.

4.3. Distillation apparatus: 4.3.1. General requirements The distillation apparatus must meet the following specifications: — the number of joints must be no more than the strict minimum needed to ensure the system is leak-tight, — inclusion of a device designed to prevent priming (entrainment of the boiling liquid by the vapour) and to regularise the distillation rate of alcohol-rich vapours, — rapid and complete condensation of the alcohol vapours, — collection of the first distillation fractions in an aqueous medium. The heat source must be used with a suitable heat-diffuser to prevent any pyrogenic reaction involving the extractive matter. 4.3.2. An example of a suitable distillation apparatus is shown in Figure 1 and includes the following parts: — round-bottomed flask, 1 litre, with a standardised ground-glass joint, — rectifying column at least 20-cm high (a Vigreux column, for example), — elbow connector with an approximately 10-cm-long straight-rimmed condenser (a West-type condenser) fitted vertically, — cooling coil, 40-cm long, — drawn-out tube, taking the distillate to the bottom of a graduated collecting flask containing a small amount of water.

The apparatus described above is intended for a sample of least 200 ml. However, a smaller sample size (100 ml) can be distilled by using a smaller distillation flask, provided a splashhead or some other device to prevent entrainment is used.

Samples are stored at room temperature prior to analysis.

Preliminary remark:

6.1. Distillation apparatus verification. The apparatus used must be capable of the following:

6.2. Spirit drinks with alcoholic strength below 50 % vol.

Measure out 200 ml of the spirit into a volumetric flask. Record the temperature of this liquid, or maintain at standard temperature (20 °C). Pour the sample into the round-bottomed flask of the distillation apparatus and rinse the volumetric flask with three aliquots each of approximately 20 ml of distilled water. Add each rinse water aliquot to the contents of the distillation flask. Note: This 60-ml dilution is sufficient for spirits containing less than 250 g of dry extract per litre. Otherwise, to prevent pyrolysis, the volume of rinse water must be at least 70 ml if the dry extract concentration is 300 g/l, 85 ml for 400 g/l dry extract, and 100 ml for 500 g/l dry extract (some fruit liqueurs or crèmes). Adjust these volumes proportionally for different sample volumes. Add a few anti-bumping granules (3.1) (and antifoam for crème liqueurs). Pour 20 ml of distilled water into the original 200 ml volumetric flask that will be used to hold the distillate. This flask must then be placed in a cold water bath (4.1) (10 to 15 °C for aniseed-flavoured spirit drinks). Distil, avoiding entrainment and charring, occasionally agitating the contents of the flask, until the level of distillate is a few millimetres below the calibration mark of the volumetric flask. When the temperature of this distillate has been brought down to within 0,5 °C of the liquid's initial temperature, make up to the mark with distilled water and mix thoroughly. This distillate is used for the determination of alcoholic strength by volume (Appendix II)

6.3. Spirit drinks with alcoholic strength above 50 % vol. Measure out 100 ml of the spirit drink into a 100-ml volumetric flask and pour into the round bottomed flask of the distillation apparatus. Rinse the volumetric flask several times with distilled water and add the washings to the contents of the round-bottomed distillation flask. Use enough water to bring the flask's contents up to approximately 230 ml. Pour 20 ml of distilled water into a 200-ml volumetric flask that will be used to hold the distillate. This flask must then be placed in a cold water bath (4.1) (10 to 15 °C for aniseed-flavoured spirits). Distil, agitating the contents occasionally, until the level of distillate is a few millimetres below the calibration mark of the 200-ml volumetric flask. When the temperature of this distillate has been brought down to within 0,5 °C of the liquid's initial temperature, make up to the mark with distilled water and mix thoroughly. This distillate is used for the determination of alcoholic strength by volume (Appendix II) Note: The alcoholic strength by volume of the spirit drink is twice the alcoholic strength of the distillate.

APPENDIX II: MEASUREMENT OF DENSITY OF DISTILLATE

The alcoholic strength by volume is obtained from the density of the distillate measured by pycnometry.

During the analysis, unless otherwise is stated, use only reagents of recognised analytical grade and water of at least grade 3 as defined in ISO 3696:1987.

A.2.1. Sodium chloride solution (2 % w/v) To prepare 1 litre, weigh out 20 g of sodium chloride and dissolve to 1 litre using water.

Usual laboratory apparatus and in particular the following:

A.3.1. Analytical balance capable of reading 0,1 mg.

A.3.2. Thermometer, with ground glass joint, calibrated in tenths of a degree from 10 to 30 °C. This thermometer must be certified or checked against a certified thermometer.

A.3.3. Pyrex-glass pycnometer of approximately 100 ml capacity fitted with a removable ground-glass thermometer (A.3.2). The pycnometer has a side tube 25 mm in length and 1 mm (maximum) in internal diameter ending in a conical ground joint. Other pycnometers as described in ISO 3507, e.g. 50 ml may be used if appropriate.

A.3.4. A tare bottle of the same external volume (to within 1 ml) as the pycnometer and with a mass equal to the mass of the pycnometer filled with a liquid of density 1,01 (sodium chloride solution A.2.1).

A.3.5. Thermally insulated jacket that fits the body of the pycnometer exactly.

The method for determining the densities in vacuo of spirits calls for the use of a twin-pan balance, a pycnometer and a tare bottle of the same outside external volume to cancel out the effect of air buoyancy at any given moment. This simple technique may be applied using a single-pan balance provided that the tare bottle is weighed again to monitor changes in air buoyancy over time.

Preliminary remarks:

The pycnometer is calibrated by determining the following parameters:

— tare of the empty pycnometer,

— volume of the pycnometer at 20 °C,

— mass of the water-filled pycnometer at 20 °C.

A.4.1.2. Calibration method using a twin-pan balance:

A.4.2.1. Using a single-pan balance. A.4.2.1.1. Weigh the tare bottle, weight T1. A.4.2.1.2. Weigh the pycnometer with the prepared distillate (see Appendix I), P2 is its weight at t °C. A.4.2.1.3. Calculation

— Mass of empty pycnometer at moment of measuring = P - m + dT — Mass of the liquid in the pycnometer at t °C = P2 - (P - m + dT) — Density at t °C in g/ml

— Express the density at t °C in kilograms per m³ by multiplying ρt °C by 1 000 , the value being known as ρt. — Correct ρt to 20 using the table of densities ρT for water-alcohol mixtures (Table II of Appendix II to the OIV's manual of analysis methods (1994), pp. 17-29). In the table find the horizontal line corresponding to temperature T in whole degrees immediately below t °C, the smallest density above ρt. Use the table difference found below that density to calculate the density ρt of the spirit at that temperature T in whole degrees. — Using the whole temperature line, calculate the difference between density ρ′ in the table immediately above ρt and the calculated density ρt. Divide that difference by the table difference found to the right of density ρ′. The quotient provides the decimal portion of the alcoholic strength while the integer of the alcoholic strength is found at the top of the column in which density ρ′ is found (Dt, the alcoholic strength). Note 4: Alternatively keep the pycnometer in a water bath maintained at 20 °C (± 0,2 °C) when making up to the mark. A.4.2.1.4. Result Using the density ρ20 calculate the real alcoholic strength using the alcoholic strength tables identified below: The table giving the value of the alcoholic strength by volume (% vol) at 20 °C as a function of the density at 20 °C of water-alcohol mixtures is the international table adopted by the International Legal Metrology Organisation in its Recommendation No 22.

A.4.2.2. Method using a single-pan balance A.4.2.2.1. Weigh the pycnometer with the distillate prepared (see part I), p″ is mass at t °C. A.4.2.2.2. Calculation — Mass of the liquid in the pycnometer at t °C = p + m – p″ — Density at t °C in g/ml — Express the density at t °C in kilograms per m³ and carry out the temperature correction in order to calculate the alcoholic strength at 20 °C, as indicated above for use of the single-pan balance.

The following data were obtained from an international method performance study carried out to internationally agreed procedures [1] [2].

Year of interlaboratory test	1997
Number of laboratories	20
Number of samples	6
Samples	A
---	---
Number of laboratories retained after eliminating outliers	19
Number of outliers (laboratories)	1
Number of accepted results	38
Mean value ( ) % vol	23,77
26,51 (*)
Repeatability standard (Sr) % vol	0,106
Repeatability relative standard deviation (RSDr) (%)	0,42
Repeatability limit (r) in % vol	0,30
Reproductibility standard deviation (SR) % vol	0,131
Reproductibility relative standard deviation (RSDR) (%)	0,52
Reproductibility limit (R) in % vol	0,37

The liquid's density is determined by electronic measurement of the oscillations of a vibrating U-tube. To perform this measurement, the sample is added to an oscillating system, whose specific oscillation frequency is thus modified by the added mass.

During the analysis, unless otherwise is stated, use only reagents of recognised analytical grade and water of at least grade 3 as defined in ISO 3696:1987.

B.2.1. Acetone (CAS 666-52-4) or absolute alcohol

B.2.2. Dry air.

Usual laboratory apparatus and in particular the following:

B.3.1. Digital display densimeter Electronic densimeter for performing such measurements must be capable of expressing density in g/ml to 5 decimal places. Note 1: The densimeter should be placed on a perfectly stable stand that is insulated from all vibrations.

B.3.2. Temperature regulation The densimeter's performance is valid only if the measuring cell is connected to a built-in temperature regulator that can achieve the same temperature stability of ± 0,02 °C or better. Note 2: The precise setting and monitoring of the temperature in the measuring cell are very important, for an error of 0,1 °C can lead to a variation in density of the order of 0,1 kg/m³.

B.3.3. Sample injection syringes or auto sampler.

B.4.1. Calibration of the densimeter The apparatus must be calibrated according to the instrument manufacturer's instructions when it is first put into service. It must be recalibrated regularly and checked against a certified reference standard or an internal laboratory reference solution based on a certified reference standard.

B.4.2. Determination of sample density B.4.2.1. If required prior to measurement clean and dry the cell with acetone or absolute alcohol and dry air. Rinse the cell with the sample. B.4.2.2. Inject the sample into the cell (using a syringe or autosampler) so that the cell is completely filled. During the filling operation make sure that all air bubbles are completely eliminated. The sample must be homogeneous and must not contain any solid particles. Any suspended matter should be removed by filtration prior to analysis. B.4.2.3. Once the reading has stabilised, record the density ρ20 or the alcoholic strength displayed by the densimeter.

B.4.3. Result When the density ρ20 is used, calculate the real alcoholic strength using the alcoholic strength tables identified below: The table giving the value of the alcoholic strength by volume (% vol) at 20 °C as a function of the density at 20 °C of water-alcohol mixtures is the international table adopted by the International Legal Metrology Organisation in its Recommendation No 22.

The following data were obtained from an international method performance study carried out to internationally agreed procedures [1] [2].