La minéralité des vins ou la conversation avec un caillou

The minerality of wines or conversation with a stone

The minerality of wines or conversation with a stone Unaware of wine, true expression of the terroir, quintessence, or simply vocabulary of the pedantic sommelier, the concept of "minerality" is in any case a vague concept which is less characterizable scientifically than semantically... Minerality in oenology is more the manifestation of a imagery of the brains that a tangible reality does not displease the poets. There is no minerality in itself, its perception results from the interaction of the different tastes of the wine with each other. This is how it exists. Apart from hackneyed images, the definition of the minerality of a wine remains “non-existent” due to lack of precise consensus. Swiss researcher Pascale Deneulin (Faculty of Letters UNIL, 2018), asking 3,500 people, professionals and amateurs, to define the mineral character of a wine, collected 50,000 terms which she arranged into textual networks. In terms of probability of association of words and ideas, “informed professionals and consumers think of the terroir, of the smells of gunflint associated with freshness in the mouth”; concepts which, however, completely escape the general public because “the less experienced consumers make the analogy with water and look for mineral elements, such as calcium and magnesium or sodium”. From a taste point of view, it is undeniable that the mineral character of a wine escapes broad agreement. Minerality is therefore just a beautiful metaphor? Another beautiful expression which often replaces the word terroir, which is also totally overused today? With minerality, some winemakers seek to oppose two worlds associated with two styles of wine: the animal world and its wines having body, fat and thigh, and the mineral world, harder, but reflecting purity and tension. , or the tension between organic and biodynamic viticulture vis-à-vis conventional, crushed under chemical inputs which prevents any possibility of expressing the potential of the Terroir. Some shots. The other opposition is that which would oppose the “primacy of the nose” to that of taste and which would obscure the perception of true minerality. “Wine is not made to be sniffed, it is made to be drunk,” Henri Jayer supposedly said. But if wine is not a perfume, it has many and the vast majority of them are perceived by retro-olfaction, that is to say in the mouth, rather than by direct olfaction….Where is the anachronism? It has been proven that the extent and sensitivity of olfactory perception of odorous volatile compounds is infinitely more generative of sensory images by the brain than that of taste and tactile perception in the mouth where minerality would be revealed. But again this is incorrect. Indeed, if we assume that minerality is only directly linked to minerals, we are wrong. It is particularly wrong to think that no mineral can produce volatile and odorous compounds. Sulfur, not that added to wine for its preservation, but that coming from the grapes via the vines, then metabolized by yeast or not, can be influenced by the nature of the soil, viticulture and then produce a fairly large number of compounds volatile. Thiols in particular are powerfully odorous molecules, which develop with aging and have aromas of a mineral character evoking for some “rock”, “heated stone” (works by Dubourdieu, Bouchilloux and Tominaga). Selenium, a trace element with a chemistry close to sulfur, is known to also produce numerous odorous volatile compounds; it is likely that they also exist in wines without us yet knowing their roles and sensory characteristics. Bromine and Chlorine are minerals well known for imparting “earthy” or “musty” odors coming from contaminating organohalogen compounds (chloro and bromoanisoles). With iodine, from the same family, they could also come from the soil or from proximity to the sea, and produce odorous compounds that remain to be identified. So what about the palatability of minerals? Opponents of this idea are often told that there are indeed (mineral) water tasters, which is a fact. On the other hand, regarding the diversity of expressions in this area, without of course denying it, we must admit that it is quite poor. “Geo-sensory” tasting does not enlighten us, to say the least, not much more. Even if it is unpleasant, all the scientific studies on the tasting and composition of wines do not make it possible to directly link the minerals in wines to the minerality descriptors. Moreover, no compound taken individually can fully explain the “mineral” character of a wine. The work carried out in our laboratory in Spain by Elvira Zaldivar (Chemico-sensory characterization of the “Mineral” attribute in white and red wines, 2017, Universidad de la Rioja) that only complex combinations between certain volatile and non-volatile compounds derived soil, such as potassium and manganese, yeast metabolism and breeding, make it possible to predict the use of sensory descriptors correlated with the notion of minerality by the taster. Finally, it seems to me that we often confuse acidity and minerality. Or again, it's quite paradoxical I admit, we talk a lot about minerality in the face of the absence of real characters in the wine... a bit like a "conversation with a stone." I was also able to read that acidity, which we more readily call liveliness when tasting wines, is “the vector for sublimating the minerality of local wines. It maintains a very subtle relationship with the mineral salts that they all contain, with great variability depending on their place of birth” according to J. Rigaux. It's nicely said, very poetic but it's not exactly true. The ground effect in the Terroir effect is not there. Of course the minerals in the soil, and not only those which are present in large quantities, play an absolutely fundamental role. But it is a role modulated via the microbiota of the soil and the rhizosphere, the clay-humus complex and the regulation of water supply. These combined parameters influence the composition of the grape in a complex way; this must then be revealed by the intervention of yeast and bacterial or even purely physico-chemical fermentation processes which ultimately result in the transmutation of the mineral component of the Terroir into wine. All this so that the wine is made to be smelled and tasted.
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