The definition of Volatile Substances was revised in 2000 in a European regulation.
For some types of spirits, the sum of volatile substances is standardized: refer to the European Regulation of Spirits Drinks in force, to the specific specifications of some appellations, or to the regulations or specifications imposed by the importing country.
This article includes the definition, the calculation and the official methods of analysis of these substances.
The analytical parameter “Obscuration” of a spirit corresponds to the difference between the real alcoholic strength by volume and the gross alcoholic strength by volume.
Where does this “Obscuration” come from?
The Practical Guide to Alcoholometry includes charts, white pages (Table VII b) and yellow pages (Table XI bb), used to determine the alcohol level at 20°C and calculate the volume of pure alcohol.
This article presents the principle of use of these charts and the differences between these 2 tables. It shows that the volume of pure alcohol calculated with the yellow pages is more approximate. It also explains how to convert at 20°C, a volume measurement when the alcohol level measurement is obtained directly at 20°C.
To achieve the accuracy provided by the manufacturer, it is important to follow the rules for using an alcoholmeter.
To maintain this accuracy, it is equally important to follow certain maintenance instructions.