ANNEXU.K.
II.DETERMINATION OF TOTAL DRY EXTRACT OF SPIRIT DRINKS BY GRAVIMETRYU.K.
1.ScopeU.K.
Regulation (EEC) No 1576/89 provides for this method only for aquavit for which the dry extract is limited to 15 g/l.
2.Normative ReferencesU.K.
ISO 3696:1987: Water for analytical laboratory use — Specifications and test methods.
3.DefinitionU.K.
The total dry extract or total dry matter includes all matter that is non-volatile under specified physical conditions.
4.PrincipleU.K.
Weighing of the residue left by evaporation of the spirit on a boiling water bath and drying in a drying oven.
5.Apparatus and EquipmentU.K.
5.1.
Flat-bottomed cylindrical evaporating dish 55 mm in diameter.
5.3.
25 ml pipette, class A.
5.6.
Analytical balance accurate to 0,1 mg.
6.Sampling and samplesU.K.
Samples are stored at room temperature prior to analysis.
7.ProcedureU.K.
7.1.Pipette 25 ml of the spirit containing less than 15 g/l dry matter into a previously weighed flat-bottomed cylindrical evaporating dish 55 mm in diameter. During the first hour of evaporation the evaporating dish is placed on the lid of a boiling water bath so that the liquid will not boil, as this could lead to losses through splattering. Leave one more hour directly in contact with the steam of the boiling water bath.U.K.
7.2.Complete the drying by placing the evaporating dish in a drying oven at 105 °C ± 3 °C for two hours. Allow the evaporating dish to cool in a desiccator and weigh the evaporating dish and its contents.U.K.
8.CalculationU.K.
The mass of the residue multiplied by 40 is equal to the dry extract contained in the spirit and it must be expressed in g/l to one decimal place.
9.Method performance characteristics (precision)U.K.
9.1.Statistical results of the interlaboratory testU.K.
The following data were obtained from an international method performance study carried out to internationally agreed procedures [1] [2].
Year of interlaboratory test | 1 997 |
Number of laboratories | 10 |
Number of samples | 4 |
Sample types |
A Brandy; blind duplicaties.
|
Samples | A | B | C | D |
---|
Number of laboratories retained after eliminating outliers | 9 | 9 | 8 | 9 |
Number of outliers (laboratories) | 1 | 1 | 2 | — |
Number of accepted results | 18 | 18 | 16 | 18 |
Mean value (
) g/l
| 9,0 | 9,1 | 10,0 | 11,8 |
| 7,8 | 9,4 | 11,1 |
Repeatabilities standard deviation (Sr) g/l | 0,075 | 0,441 | 0,028 | 0,123 |
Repeatabilities relative standard deviation (RSDr) (%) | 0,8 | 5,2 | 0,3 | 1,1 |
Repeatabilities limit (r) g/l | 0,2 | 1,2 | 0,1 | 0,3 |
Reproductibility standard deviation (SR) g/l | 0,148 | 0,451 | 0,058 | 0,21 |
Reproductibility relative standard deviation (RSDR) (%) | 1,6 | 5,3 | 0,6 | 1,8 |
Reproductibility limit (R) g/l | 0,4 | 1,3 | 0,2 | 0,6 |