Definition of Volatile Substances according to European Regulation

According to Regulation (EC) No 2870/2000 of December 19, 2000, the sum of the following compounds is taken into account:

• Sum of Higher Alcohols (propanol-1, butanol-1, butanol-2, isobutanol, methyl-2 and methyl-3 butanol-1) in g/hl of pure alcohol
• Total aldehydes (acetaldehyde=ethanal + acetal expressed as ethanal) in g/hl of pure alcohol
• Ethyl acetate in g/hl of pure alcohol
• Volatile acidity expressed as g of acetic acid in hl of pure alcohol

Changes in the regulation include:

• The concept of “on-alcohol coefficient” diseappers
• Furfural and phenyl ethanol are no longer part of the official definition of volatile substances
• Only Ethyl acetate should be taken in account, no more “Total Esters“

Only  ethyl acetate should be considered because the methods based on the chemical measurement of total esters can overestimate the calculation of the sum of Volatile substances.

Consequence:
Specifications for spirits that require a minimum of volatile substances should take into account that this new definition leads to a lower result in volatile substances.

Analysis Methods for Volatile Substances

Higher alcohols, Total aldehydes, Ethyl acetate

Only gas chromatography methods allow good selectivity of these compounds.
There are global chemical methods, but they are not specific and can overestimate the quantity of volatile substances.

Volatile Acidity

The volatile acidity of spirits is composed of various volatile acids.

The definition of the official method corresponds to the difference between total acidity and fixed acidity.
Total acidity is measured by titration with sodium hydroxide. Fixed acidity is measured in the dry extract by titration of the total acidity.

Their is an other method by titrating volatile acidity with sodium hydroxide in a distillate of steam distillation. But this method may underestimate the value. Unlike wines, where the measurement of acetic acid can be equated with volatile acidity (1), spirits can contain volatile acids that are not all carried over in the distillate.

However, for certain “liqueurs” containing excessive amounts of sugars, volatile acidity can only be obtained through steam distillation.

Calculation Units:
The standards imposed for volatile substances and sometimes other volatile compounds, such as furfural, are generally expressed in grams per hectoliter of pur alcohol (g/hl P.A.).
Altough Volatile acidity should be expressed in g/hl P.A. of acetic acid, some importers standards or specifications may require other units (e.g., mg/l; mg/cm3; l/dm3).

To facilitate and ensure the reliability of these conversions, Labox has provided the “Unit Conversion” Boxette.

1. ETUDE COLLABORATIVE DE COMPARAISON DE L’ACIDITE VOLATILE ET DE L’ACIDE ACETIQUE DANS LES VINS
   Réalisée sous l’égide de l’union des Œnologues de France Coordinateur : Matthieu DUBERNET – Article technique RFOE n°221, page 7 –http://dubernet.com/pdf/publications-scientifiques/rfoe221.pdf