Among the many components found in wine, alcohol certainly is the most deplorable one. Not because it is alcohol, indeed for the notable effects it can cause to the organism. On this regard, it should be noticed nothing is good or bad: it is always the use, or the abuse, one makes of it to make it either one or another. In fact, what gets alcohol under accusation are the consequences derived from its abuse, of course not for its moderate and intelligent consumption. It is not in fact anything new the moderate and wise use of alcohol can also be beneficial for the organism, whereas the abuse - in this case everyone agrees on that, no exception - besides being an idiot and foolish act, which is not justifiable and agreeable in any case, it is frequently cause of damages to the organism, also chronic and irreversible. Pleasure is different from the disgraceful condition caused by dependency, in particular when it causes deprecable consequences both for oneself and others.

 Good and right, bad or wrong, alcohol is however a fundamental component in wine, it probably is the element which historically determined the interest of humans towards this beverage during the journey of the history of human beings. Poets, writers, historians and philosophers of every era, have always praised the virtues of wine and of that characteristics it had to give joy and cheerfulness, to relief the soul, corroborate the spirit and body. In every culture and society in which wine was found, it was always considered as a sacred beverage, destined to the most significant rites, probably because of the inebriating effects of alcohol, as well as for the association - in particular red wine - it could easily evoke with the sacred liquid which could maintain humans alive, that is blood. On this regard, it could be mentioned the eucharistical use of wine in Christian religious rites, taking its origin from this analogy.

 It is now some time market is offering wine without any alcohol in it, produced with an industrial process called dealcoholization, however the importance of alcohol in sensorial tasting and in wine balance is fundamental. On this regard, it should be noticed wine is produced by the alcoholic fermentation of grape juice, a process that, unavoidably, brings to the production of alcohol and, in case it is not properly done, to the production of vinegar. The wine itself exists because of the existence of alcohol and the complex biochemical process producing it thanks to the action of yeast, but - this must be said and remembered - wine is not alcohol only. If we consider the average content of alcohol in wine, this generally represents 13% of the beverage, therefore it is not the main element. Wine, as it is commonly known, is a complex beverage, not only from a sensorial point of view, but also from a chemical point of view, where alcohol represents one of the hundreds of element making it.

 Alcohol, like already said, is the result of fermentation, a biochemical process done by yeast, unicellular organisms that, in absence of oxygen, convert sugar into ethyl alcohol and carbon dioxide. Fermentation, as a matter of fact, is the process ensuring survival to yeast when there is no oxygen available, thanks to the conversion of sugar. At the beginning of this complex process, yeast can survive in condition of aerobic breathing - that is, in presence of oxygen - and during this stage sugar is converted into water and carbon dioxide. When the oxygen has been completely consumed, the process continues in anaerobic conditions - that is in absence of oxygen - and it is during this stage the process is called fermentation, ensuring survival with the energy obtained from sugar only. Fermentation is however a process leading to a lethal end for yeast, both because of the consumption of the only energy source, sugar, as well as because ethyl alcohol, when found in high quantity, is toxic for their survival.

	Clear and limpid: alcohol in its pure form shows as a transparent and crystalline liquid

 The fermentation process therefore ends - provided favorable environmental conditions - both because of the total consumption of sugar, as well as for the high quantity of alcohol that in certain cases is produced by yeast. Without sugar, yeast have no possibility of survival and of nourishment, a condition which unavoidably brings to the end of the biological activity, leaving to the liquid a certain quantity of ethyl alcohol. It should be said the process of fermentation also produces other substances, although in lower quantity than ethyl alcohol, among the many, the “famous” and widely debated sulfur dioxide. At the end of fermentation - technically called alcoholic or primary - yeast will give back grape juice transformed into wine, a complex beverage and characterized by countless aromas and flavors, in which ethyl alcohol plays a fundamental role. It should also be said the so called alcohol free wines are produced by this very process, to which, at the end of fermentation, alcohol is eliminated by using specific methods, in particular, the most common ones are inverse osmosis and cold distillation.

 For the sake of information, it should be said sometimes the process of dealcoholization is used for table wines as well in order to lower the alcohol volume of few units. Blind tasting tests done on dealcoholized wine, or partially dealcoholized wines, have proven the process of alcohol removal also removes other components of wine, in particular aromatic substances. In fact, alcohol plays an active role in the perception of gustatory substances, and in particular, olfactory substances. This can be explained, among the many factors, thanks to the capability of alcohol to volatilize, by literally lifting up aromatic substances from the surface of wine, therefore favoring their olfactory perception, both intensity as well as quality and variety. For this reason, most of the times systems used for dealcoholizing wines provides for the recovery and subsequent reintroduction in the wine of the aromatic fraction extracted during the removal of alcohol, a reintroduction that - in any case - will not have the same intensity and quality of its original form.

 Alcohol by volume currently found in table wines has an average value of 13.5%, however it is not rare to find value reaching 14.5%, sometimes even higher than that. In past times, however not so distant, alcohol by volume was lower, with an average value of 12.5%, a value that, not only represented the average volume, but also considered as average-high. Today this value is considered as average-low and it is pretty hard to find wines with an alcohol by volume of 12.5%. The reasons for the increasing of alcohol by volume are many. Climate changes of the last years, characterized by a pretty hot and torrid summertime, greatly affected the ripeness cycle of grapes and, with that, the development of sugar, therefore increasing their quantity. Yeast, like already said, use sugar to conduct fermentation: with a higher quantity available, fermentation is longer and, at the same time, it is also produced a higher quantity of alcohol.

 Alcohol is one of the many elements contributing to gustatory balance of wine, specifically, it is one of those components defined as soft, that is useful in balancing all the substances defined as hard. As it is commonly known, one of the primary characteristics defining quality in wine is balance. An excessively round and smooth wine - a sensation to which alcohol contributes - makes the gustatory profile of wine flat and dull, without any trace of lively touch. A too much alcoholic wine, and not properly balanced, will in fact cause this sensation in the mouth, besides being too much “hot” because of the typical caustic and irritating effect on taste buds. The typical tactile sensation of alcohol can in fact be diminished by a proper balance, such as increasing astringency or acidity in a wine.

 It should be noticed balance of alcohol does not lower the quantity found in a wine, it simply lowers its perception. This means that, at the taste, a wine can be perceived less alcoholic than it is for real, however the quantity of alcohol does not undergo any kind of change. We can consider, for example, a wine produced with the Nebbiolo grape. Fermentation of the must of this grape tends to produce significant quantity of alcohol - sometimes higher than 14% - however the presence of acid substances and astringency, both the typical astringency of the grape as well as the one of the cask, make the wine balanced and, with that, also the alcoholic sensation perceived in the mouth will seem milder. It is therefore a relative perception and not quantitative one, a concept valid for every other olfactory or gustatory stimulus. Moreover, the perception of a stimulus and its intensity are also determined by the threshold of perception of each subject.

 Before discussing the organoleptic aspects associated to taste and the contribution of alcohol in a wine's gustatory profile, let's focus on the role played by this element in the perception of aromas. Ethyl alcohol is a volatile substance, therefore - as such - it tends to “lift up” from the surface of the wine and to dissolve in the air. During its volatilization, alcohol is extremely useful in the perception of aromatic substances, as it literally transports these elements upwards, therefore making their perception to the nose easier. Like already said, a wine with a low content of alcohol - or with no alcohol - seems to be less aromatic and certain olfactory components are quite attenuated and more difficult to perceive to the nose. There is however an exception to that as wines produced with the so called “aromatic” grapes, such as Muscat Blanc and Gewürztraminer, thanks to the abundance and the intensity of their aromatic components, are however well perceptible even without the help of ethyl alcohol. For example, we could consider Moscato d'Asti: despite its alcohol by volume is usually about 5%, its aromatic strength is however well perceptible.

 According to a gustatory point of view, alcohol is perceived in the mouth by means of many organoleptic sensations, both gustatory as well as tactile. The most evident and dominant sensation of alcohol is of tactile nature. The more evident tactile effect produced by alcohol is recognizable in a sensation recalling heat, usually described as a pseudocaloric effect. This caustic effect is the consequence of dryness of mouth's mucosa produced by alcohol, an irritation which can be easily confused with a “burning” sensation. The higher the quantity of alcohol, to be precise, the more the alcohol in wine is unbalanced, the stronger the burning sensation it produces. We could consider, for example, the effect of a distillate, in which the quantity of alcohol is pretty high and, although balanced by other components, the burning sensation is evident and can also last many seconds.

 When the tactile burning sensation will be over, it will finally be possible to perceive the taste of alcohol, which is basically sweet. It is not an “evident” sweetness as in the case of sugar, however the sweet sensation will be well perceptible in the taste of alcohol. Another gustatory-tactile characteristic of alcohol is roundness produced in the mouth: for this reason, and because of its basically sweet taste, alcohol is classified among “soft” components in the determination of a wine balance. Its gustatory excess - sweetness and roundness - must therefore be properly balanced by “hard” substances, such as astringency, acidity and a quantity of mineral elements. On the other hand, its presence will be useful in balancing the excess of both acidity and astringency found in a wine, therefore useful both in white wines, where acidity is a characteristic element, as well as in red wines, in which we have both acidity and - in particular - astringency produced by tannins.