Evaluation of the hedonic tone

The evaluation of the hedonic tone allows to determine the pleasantness-unpleasantness of an odor and is carried out according to the VDI 3882 Standard, in an olfactometric chamber.


Tone evaluation issuitable for assessing the potential pleasure or annoyance of a given odor byobjectifying a subjective perception. The examiners used in the analysis panelmust be previously selected based on the response to two reference substances(guaiacol and vanillin).


Stages of activity:

  • The odor concentration of the odorigenous sample (UNI EN 13725: 2004) is preliminarily determined and, once this data has been acquired, it is possible to identify the concentration range of the odor to be presented to the examiners; 
  • The odorous stimulus is presented, with a random concentration within the established range, to the examiners using the olfactometer. The stimulus is presented for 15 seconds, with an additional 5 seconds of decision-making time and a minimum pause of at least 1 minute between two stimuli; 
  • By analyzing different dilutions of a sample (even below the threshold of perception), the examiners associate a number from - 4 to + 4 with each perception; 
  • After evaluation in the olfactometric chamber, statistical calculations are carried out to evaluate the relative cumulative frequency at the different dilution steps analyzed, determining the correlation between the dilution of the odor and the pleasantness / unpleasantness of the odor itself; 
  • Finally, thecharacteristic curves of the hedonic tone are obtained, with the values ​​ofthe honic tone obtained and the odor units of the analyzed samples in abscissa.

Lod boasts important collaborations in this sector, such as, for example, for the evaluation of the correct action of products for cosmetics and personal hygiene.


LOD: Laboratorio Olfattometria Dinamica

Spin-off dell’Università degli Studi di Udine