4 STEPS INTO THE SENSORY WORLd OF WINES
IMPORTANCE OF OUR SENSORY SYSTEM IN THE EVALUATION OF WINE
Sensory analysis in tasting and technical tasting is something fascinating. At first glance, one might think that learning the tasting technique or evaluating a wine does not require knowing the neurophysiological or psychophysiological mechanisms that allow us to learn or evaluate. Wine is a drink well known by technical tasters, but it is also appropriate that the Technical Taster must know himself and how his sensory apparatus works, to best evaluate the wine.
Wine tasting, when it leads to a professional evaluation, is a complex process, which does not only concern the object of the tasting (the wine), but also the physiological conditions of the person who performs it. Let’s say that when we identify and define a smell, a flavor or a quality, we express it with a word, which is the outcome of our brain that governs all our receptors that are allocated in our senses. Tasting a wine brings into play a series of sensory stimuli that are provided by the savory and odorous constituents of the wine itself.
Let’s start with small hints, let’s talk about the first sense organ which is SIGHT. Sight is very important, because through this, we can give an evaluation of 40% of the wine.
Through this sense we can evaluate the:
Clarity – The color with its tone, intensity, and vivacity,
The color tone is the actual color of the wine, for example straw yellow or ruby red, influenced by multiple factors that also weigh on the intensity of the color, such as, for example, the acid profile of the wine.
The intensity of the color, strongly connected to the shade, depends in turn on many elements: vine, soil, degree of ripeness, health of the grapes, winemaking process and refinement of the wine.
The Vivacity of a wine is a fundamental aspect that can provide a series of information on the quality and age of the wine itself. The vivacity of the color is very important to understand if the production and evolution process of the wine has occurred correctly. It depends on: State of health of the grapes – degree of ripeness of the grapes. Processing techniques – Conservation – environmental factors. It is evaluated by holding the glass tilted on a white sheet, it is expressed by the following adjectives: dull – opaque – lively.
The viscosity and through this phase of the visual examination we observe: – how the wine “descends” as we pour it into the glass; – how the wine behaves after a rotary movement has been impressed on the glass. The “arches”, which form along the walls of the glass, are mainly caused by the alcohol which, together with the glycerine and sugars present in the wine, contribute to determining the density or fluidity of the wine itself.
The effervescence of frizzanti and sparkling wines, one must evaluate the number and fineness of the bubbles, their persistence and the nature of the trail (the sequence of bubbles that develop in the glass, flute, is normally called perlage).This first examination is very important, it raises expectations and prepares our senses for other evaluations. The appearance predisposes to the point of anticipating our judgment, in fact, if the appearance of a wine is pleasant and beautiful, we are already led to think that it can only have high quality
In tasting, in chronological order the second sense involved is SMELL.The human sense of smell has an enormous receptive power, with a sensitivity 10,000 times greater than that of taste. There are two ways to olfactory evaluate wine: directly (orthonasal), by inhaling it, and indirectly (retronasal), by exhaling it, when it is contained in the oral cavity.
You will often observe people chewing wine, nothing imaginative. When you “chew” wine, the communication between the pharynx and the nasal passages is interrupted, a communication that is re-established when you swallow or expel it. It is at this point that the odorous substances are able to free themselves from the particles of the liquid that impregnate the mucous membranes of the mouth and are transported through the nasopharynx to the olfactory bulb.
The olfactory sensations that are captured in wine derive from the presence of volatile odorous substances of a chemical nature. In literature, but the distinction is not unanimous, we read about odors and aromas. The former are perceived directly from the glass, while the l Some still divide into primary, secondary and tertiary odors/aromas, meaning that the former refer to the characteristics of the fruit, the latter concern the fermentation products and the latter express the odorous constituents of the refinement. Atter are perceived retro-olfactory. In tasting, the last step is the Gustatory examination. First of all, I would like to report the observations of Francis Leukel, a psychologist at the University of San Diego: «Sensitivity to taste is caused, in adult humans, by receptors on the tongue… Sensitivity is also found in the palate or roof of the mouth and in the larynx. Taste receptors give rise only to sensations of sweet, salty, sour and bitter; the complex of subtle sensations called “taste” in everyday language includes smell, common chemical sensitivity and bodily perception». The word taste is therefore ambiguous because it has more than one meaning: it can represent the 4 tastes of wine or it can represent the set of perceptions that originate in the mouth.
The perception of the 4 tastes, with a little training, is relatively simple. The definition of the perceptions derived from wine in the oral cavity is decidedly more complex because the remaining perceptions listed above are added to the 4 tastes.
Recent studies conducted by neurobiologists have led to the consideration that the perception of odors through the retronasal route is predominant and can constitute 75-80% of the entire perception of the oral cavity. Some scholars suggest identifying this type of perception with the term “flavor” to avoid possible misunderstandings. It is a very complex examination and involves, as seen, several senses. When you have a wine in your mouth, you first perceive the actual taste sensation, followed by the tactile/chemical, thermal/pseudo-caloric and retronasal olfactory ones.
The TASTE test in the strict sense is limited to the five basic tastes: sweet, acid, salty, bitter and umami. The latter is not present in wine and therefore cannot be assessed. Unlike aromas, tastes, even when combined, maintain their individuality. Normally the first sensation you experience is sweet, then comes acid, then salty and finally bitter.
In the evaluation of a wine according to the ONAV sheet, the analysis of the individual tastes is not required, but in fact they are also included in the overall evaluation that we have seen constitutes the flavor. It may therefore be useful to dedicate a few lines to the role they play.
Sweet
This taste, which is generally perceived on the front of the tongue, is essentially given by sugars (glucose and fructose), ethyl alcohol and glycerin.
Acid
Wine is an acidic drink. Acidity is generally perceived on a fairly large surface of the tongue located along the edges and under the tongue itself. The right (another improper term, but widely used) level of acidity is one of the important factors that make wine pleasant; in fact, in addition to giving it a sense of freshness, it enhances the liveliness of its color and increases its resistance to alterations. The acidity of a wine must respect certain rules: if excessive, the wine will seem hard, aggressive and disharmonious; if too little, the wine will be weak, flat and lacking in character.
Bitter
This sensation is perceived especially in the back of the tongue. This taste is characterized by a notable persistence that, in general, is due to the presence of quinones, derived from the oxidation of phenolic substances, tannins and coloring matter. The presence of alcohol and sugars can, to a certain extent, attenuate this sensation. It is frequently associated with astringency (tactile sensation) and it is not always easy to distinguish this from that perception, as bitterness and astringency can be cumulated. Increasing the astringent substances increases the intensity but not the duration; on the other hand, increasing the bitter substances increases both the intensity and the duration. It is quite difficult, if appropriate precautions are not taken, to evaluate whether the measure of the intensity of the bitter taste, expressed by yet another sample, is due to the intensity truly perceived or rather to the phenomenon of accumulation determined by too many samples tasted.
Salty
This taste, perceived mainly along the edge of the tongue, is attributable to the fact that in wine there are 1.5-3 g/L of mineral salts of potassium, calcium and magnesium. In truth it is a taste, as such, rarely perceptible. It is the salts that give wines that pleasant sensation of saltiness that alcohol and volatile substances tend to mask.
Tactile/chemical sensations
In addition to the five basic tastes, the central epidermal tissue of the tongue and that of the oral cavity perceive other physical stimuli: it is the tactile sensations that play an important role in the overall evaluation of the quality of the wine. These sensations, which are given by the presence of tannins, glycerin, sugars and carbon dioxide, allow us to evaluate the body, fluidity, oiliness and gustatory balance of the wine in question.
Thermal and pseudo-caloric sensations
When tasting, you can also experience thermal sensations given by the temperature of the wine, because the latter influences qualitatively and quantitatively all sensory perceptions. This is the reason why you should never taste a wine below 8 °C and above 22 °C. In a wine you can also perceive a pseudo-caloric sensation that is given by the quantity of ethyl alcohol present. Since this sensation can be attenuated by the presence of acids, if alcohol prevails in the alcohol-acidity ratio, you will have a sensation of heat; if acidity prevails, you will have a sensation of freshness (a term that expresses an organoleptic character of the wine and that has nothing to do with temperature).
Interactions
The set of all the sensations perceived during tasting influences what is called the gustatory balance of the wine. Let us keep in mind that between the various gustatory sensations there is a kind of interaction, also called the “mixing effect”. In general, all the fundamental tastes show this inhibitory behavior, called “suppression of the mixture”. Here are some examples:
– acidity and astringency mutually reinforce each other, but can be attenuated by sugars;
– carbon dioxide reinforces the impression of astringency;
– the pseudo-caloric impression of alcohol is inversely proportional to acidity;
– according to some, alcohol can attenuate bitter sensations, but according to others, alcohol would increase them by promoting the permeability of lipid membranes;
– the presence of sugars masks the bitterness but not the astringency.
Of course this is just a smattering of information on this splendid topic that will be exhaustive in the courses. If you have any questions you can leave them on the blog or even on the email
canada@onav.it