Tasting a food product is a temporal experience; this is especially true for certain types of products that remain in the mouth for quite some time (chewing gum, wine, etc.), but also for any type of products, whether food or not…
Classic sensory analysis methods, such as the sensory profile for example, have a downside because they are based on static judgment. As a matter of fact, panelists only assess each descriptor for the duration of the assessment and are unable to modify their judgment over time. As a result, products that provide very different sensory experiences over time might be considered similar when tested with those static methods.
A dynamic method called Temporal Dominance of Sensations, or TDS, was developed in 2000 in Dijon in order to assess the evolution of several sensations over time simultaneously. This method simply consists in submitting to panelists a list of attributes and asking them to choose which attribute they feel is dominant over time, i.e. which attribute captures their attention most, during the entire tasting session.
Once a few calculations are made and “Dominance Curves” are plotted, the TDS provides general temporal information over the duration of a tasting session, thus making it possible to highlight differences between products that would be left unnoticed with classic methods.
That being said, when can we use this test?
As a rule of thumb, you can use it whenever you suspect that the sensory characteristics of your products change over time…
For example, one of our clients wanted to find out what made their products (cereal bars) different from those of their competitor, whose products were preferred. Both products seemed to be very similar, but even with a sensory profile test, the client was unable to find substantial differences explaining consumers’ preference for the competitor’s products. We carried out a dynamic test using the TDS method and discovered that, contrary to their competitor’s, our client’s products left a bitter taste that lingered in the mouth and that consumers did not like… The formulation team then knew what to do to improve the product!
The TDS is now a very popular tool in sensory analysis and has undergone a variety of methodological developments: dynamic measurement of preferences, multi-bite measurements, interactions between several types of products… But that is another story. 😉