The ability, odor and taste to perceive and also to identify substances is a complex process involving the participation of multiple senses. The six taste sensations sweet. angry. salty. bitter. umami and greasy be over the palate and tongue gustatory perceived. On the other hand, there are around 10,000 different odors (fragrances) that humans can recognize or, if they have the corresponding experience, could. These are over the olfactory mucosa olfactory perceived.
Odor and taste sensations are still supplemented with haptic (tactile) or trigeminal Tactile, temperature and pain information from the oral cavity. These include, for example hot and sharp who do not "taste" older with "smell", but have to do with "feel". The impressions received via the tongue, palate and nose mix in the brain to an overall impression, so that the definitive origin is no longer clear or unequivocal to understand.
It depends on the amount of odorants and flavors, from when the substance is perceived. This quantity is very different depending on the substance. Extremely small quantities in the billionth of a gram range are already sufficient for the mottoes in the wine-causing substances (see a table in this respect below) wine faults ). This limit is called the perceptual threshold (boundary) and divided into four thresholds:
The stimulus threshold (also absolute threshold ) denotes the sensation of an indefinite smell or taste. This means that you smell or taste something, but no definition of the substance is possible. At the detection threshold , the substance is clearly recognized and defined. At the saturation threshold, a further increase above the detection threshold is no longer possible. The discrimination threshold relevant in comparative tests of, for example, two wines is the difference in concentration above which, in addition, a qualitative difference can be established.
For the four terms described above, the threshold value is that value which, under specified conditions, can be correctly perceived by at least 75% of wine tasting examiners. In these, the ability to perceive and correctly identify is strong. That plays in the wine review or quality control plays an important role. Concrete examples are the award of the Official test number (Germany) and the State test number (Austria). In food testing increasingly used in wine tastings QDA (Quantitative Descriptive Analysis) tests are also performed on the perceptual thresholds of the individual examiners.