Among the many types of wines, the ones which are capable more than any other else to evoke rich emotions and to excite senses the most are probably sweet and botrytised wines. In the course of centuries these wines have always been appreciated and looked for in every place, considered real and proper nectars for their aromatic qualities and for their enchanting and intense flavors. They were also considered as medicines and reconstituents; it is often cited in ancient documents that doctors prescribed these wines as a cure. The charm of these wines could also be because of the fact they are usually produced in limited quantities and in tiny areas, two factors which certainly contribute to make rare, and therefore precious and valuable, these genuine nectars of grape.

 The production of sweet wines, with the exception of sweet sparkling wines, are always based on the usage of grapes which lost part of their water while obtaining a concentration of juice and a higher quantity of sugar. The reduction of water in grape's berries is a natural process which takes place in two different ways: by leaving bunches on the vine and waiting for berries to get dried, or to harvest grape when it reached full maturation and to let it dry in protected and well aerated rooms, placed in mats or hanged. The most common method is the one of allowing bunches to get dried on the vine, mainly in those places where particular climatic conditions promote the development of a mould, apparently a negative factor, which in reality adds unique and extraordinary characteristics to the wine. This particular mould, to be considered as a real and proper blessing, whose scientific name is Botrytis Cinerea, is capable of giving grapes where it gets developed, truly unique aromas and flavors and, because of its effects, it greatly contributes to water reduction in grape's berries.

 The development of this mould, usually called noble rot, exclusively takes place in areas where particular environmental and climatic conditions allow its formation on the skin of grape's berries. The effect of noble rot in sweet wines, for this reason they are also called botrytised wines, is always a positive factor because it is capable of giving wine unique and extraordinary aromas and flavors, very difficult to explain with words or with the help of analogy, and they become absolutely unmistakable after having perceived them for the first time. The most common and frequent definitions used to describe the aromas added by noble rot to wine include honey, spices, apricot, hazelnut, toffee and caramel; honestly no one of them can describe it fully, maybe they can just give a vague idea, what it is certain is that aroma of Botrytis Cinerea is unique, pleasing, elegant and very appreciated. This precious mould is called muffa nobile in Italian, pourriture noble in French, edelfäule in German and Aszú in Hungarian; in every country is always and however welcome in vineyards and allows the production of great, magnificent wines.

	Sweet wines: sweet moments of life

 The first witness about the discovery of noble rot's effects on wine is dated back to the half of seventeenth century by a Hungarian priest, but it seems it was already known to Greeks more than 2000 years ago. The development of noble rot, which needs particular environmental and climatic conditions, in particular favorable conditions of humidity, is frequent in certain areas of Hungary, Austria, Germany, France, Italy, Australia and North America. The development of noble rot is pretty unpredictable, it requires good humidity for its formation and a dry climate in order to survive. The repetition of these climatic conditions and in subsequent days, in particular cool and moist nights followed by warm and dry days, ensure the development of noble rot which usually appears on grapes after two or three days. Noble rot usually prefers white berried grapes having a pretty thick skin and with compact bunches, and in case climatic conditions are not favorable, in particular when humidity is excessive and prolonged, it could easily degenerate into another type of mould having opposite effects: grey rot, a factor which irremediably ruins grapes and therefore cannot be used for producing wine. The development of noble rot in vineyards truly is a preoccupying event for every viticulturist because in case conditions are not favorable, precious and valuable grapes can turn into unusable and rotten grapes, a preoccupation that ends only after harvesting.

 When the spores of Botrytis Cinerea get in contact with the moist skin of grape, usually transported by wind, they start consuming the water on skin's surface and therefore they increase in dimension. At this point begins the development of a germinal tube which holes the skin in the aim of searching nourishment. As the mould gets into the berry, and also thanks to the huge quantity of nutrients, the development is pretty rapid and the surface of the skin gets literally covered by noble rot. Holes made by spores in the skin promote the reduction of water, therefore concentrating sugar and aromatic substances. The effect of noble rot continues by transforming some substances present in grapes and get mixed to them therefore adding its aroma and its flavor. At the end of the process grape's berries have a look which is not certainly inviting, apparently rotten, but on the inside took place unique magic that will give origin to a divine nectar.

 Typical colors of sweet and botrytised wines depend, first of all, by the species of grapes used for their production. In sweet red wines, such as Recioto della Valpolicella or Sagrantino di Montefalco Passito, the range of colors is pretty common, usually ruby and garnet red, very deep and most of the times impenetrable by light, with nuances of garnet red. In sweet white wines the range is wider and colors can go from golden yellow to amber yellow, sometimes very dark. The color of sweet white wines mainly depends by the way grapes were dried as well as the type of grape. Generally speaking sweet wines produced with grapes dried after harvesting usually have deeper and darker colors and tend to amber yellow, such as Vin Santo produced in Umbria and Tuscany or Moscato di Pantelleria Passito. It should be however remembered that amber color could also be the sign of oxidation, sometimes wanted by the producer in order to give wine particular organoleptic qualities.

 Sweet white wines produced with grapes dried on the vine and, in particular, grapes affected by noble rot, such as Sauternes, German and Austrian sweet wines, as well as botrytised wines produced in Orvieto (Umbria), are characterized by splendid golden yellow colors, brilliant and intense, however amber yellow is frequent as well, such as the one of Tokaji Aszú. The color of sweet white wines tends to get darker with the aging in bottle, changing from golden yellow to dark golden yellow and then to amber yellow.

 Aromatic characteristics of sweet wines produced with dried grapes are pretty complex and change according to the type. A characteristic which is usually common to every sweet wine produced with dried grapes is the richness and intensity of aromas, sometimes seems that every time the glass is being smelt a new aroma is coming out from it and the list seems to be endless. In sweet wines produced with red berried grapes will be frequent aromas of red and black skinned fruit, such as plum, strawberry, blackberry, black cherry, cherry, blueberry, raspberry and black currant, sometimes also perceived as jams made with those fruits. Dried flowers can be found as well, such as violet and rose, as well as particular aromas, such as chocolate and cocoa, and spices, such as cardamom, cinnamon and vanilla, in case the wine was aged in cask.

 In sweet white wines the aromatic range is certainly more variegated and complex. In sweet wines produced with aromatic grapes, such as Moscato di Pantelleria, Malvasia delle Lipari and Moscato Passito di Chambave, the aroma of grape will be very pronounced, often resembling raisin. In wines produced with grapes affected by noble rot, such as Sauternes, Tokaji Aszú and Muffato di Orvieto as well as German and Austrian sweet wines, the aromatic effect of Botrytis Cinerea will be evident and often very pronounced. The pleasing and elegant aroma of noble rot is, like we already said, pretty hard to define with words or with the help of analogy, many have compared it to the one of honey, spices, apricot, hazelnut, toffee and caramel, no one of them really resemble to it, maybe, it could be defined as a combination of them all in different proportions.

 In these wines is the aromatic range of fruit to dominate, most of the time it is dried fruit and jams, such as apricot, peach, quince, pear, apple and fig, as well as tropical fruit, such as banana, litchi, mango and pineapple. Common are also aromas of flowers, often dried, such as acacia, orange blossom and broom. The aromatic series in sweet white wines continues with aromas of candied fruit, in particular orange peel and other citrus fruits, honey of many types of flowers, caramel, chocolate, croissant, almond and hazelnut. Sometimes can also be found aromas of spices, such as cinnamon, anise and vanilla, in particular when the wine was aged in wood containers. Typical aromas in sweet white wines are countless and, in general terms, very complex, in wines aged in bottle for many years the aromatic range gets richer, often so surprising that one would not even expect to find them in a wine.

 As a sweet wine enters the mouth, it is more likely the impact is pretty surprising. Its flavors are usually intense, having a good correspondence to the aromas perceived by the nose, sweetness is clearly perceivable from the very beginning and a pleasing sensation of velvety roundness pervade the mouth. A pleasing characteristic of these wines is their very long taste olfactory persistence, like no other wine. It is not rare to find a sweet wine with a taste olfactory persistence longer than 15 seconds and sometimes they can even be measured in minutes instead of seconds.

 Despite the fact this premise could make sweet wines appear like a heavenly nectars, and they certainly can be like that, what makes these wines pleasing and extraordinary to the taste is their balance. Because of the presence of sugar, these wines could taste sickly and syrupy in case they are not properly balanced by other components. Because of the different quantities of substances present in white and red sweet wines, it is necessary to distinguish balance of the two types. The characteristic common to both is certainly alcohol and sugar, whereas in sweet red wines it is common the presence of tannins, and therefore of the tactile sensation of astringency; in white sweet wines the quantity of acid is higher, usually can be appreciated to the taste as well.

 The critical factor in sweet wines is represented by the quantity of residual sugar and from this factor also depends the whole balance. Alcohol, which basically has a sweet taste, partially has a role in the balance of sugar as its pseudo caloric action lowers the relative perception of sugar. In sweet red wines, where tannins can be found, sugar has a balancing function for astringency as it basically tends to attenuate it, the same function is also done by alcohol. Moreover it should be remembered sugar tends to slow down the perception of astringency. In sweet white wines it will be acidity to play an important role for balance. Sweetness and acidity tend to balance one each other, sugar will therefore balance a very acid wine, whereas acid will avoid a wine to taste sickly or syrupy. This is the specific case of German sweet wines, despite the fact they have a high acidity, they are very balanced thanks to the mutual tendency of these two components to balance each other: the wine will never be sickly nor acid, but perfectly and pleasingly balanced.

 In this practical application on sweet and botrytised wines we will use three wines having particular characteristics: an aromatic sweet wines, a sweet wine and a botrytised wine. We will examine a Moscato di Pantelleria Passito, a Vin Santo from Umbria or Tuscany, and a Muffato di Orvieto. Despite there is a very personal preference about serving temperatures for sweet wines, in our case we will taste the wines at a temperature of 14° C (57° F) in order not to penalize the development of aromas and without excessively enhancing sweetness. In the evaluation of appearance the three wines will have very different colors whereas “consistency” and viscosity will seem to be the same: by rotating the glass it will be noted a higher density of the liquid if compared to any other wine. Moscato di Pantelleria Passito will show an amber yellow color tending to a pale tint; Vin Santo will be the one having a deeper and more intense color compared to the others, in this wine the amber yellow color will be darker and deeper. The Muffato wine will show a brilliant and intense golden yellow color.

 To the nose the three wines will offer very different olfactory perceptions, however they will all be characterized by a strong intensity of aromas. In the Moscato di Pantelleria Passito it will be perceived, in the beginning, a pronounced and pleasing aroma of grape, a primary characteristic of the wine, followed by aromas of dried fruit and jam, such as dried apricot, candied fruit, peach jam, almond, dried fig, citrus fruit peel and orange marmalade. Moreover will be perceived aromas of tropical fruit such as litchi. The aromas of Vin Santo will seem to be more complex and in particular it will be perceived a clear aroma of fig jam and caramel, as well as aromas of jams, such as apricot and peach, and dried fruit, such as dried fig, almond, dried apricot and raisin. Other aromas that can be found in Vin Santo include honey and vanilla, in case the wine was aged in casks, according to the traditional process for the production of this wine. In the Muffato di Orvieto the aroma of noble rot will clearly be perceivable from the very beginning. This aroma, truly particular, is pretty hard to describe by means of words, however it is easily recognizable after having perceived it for the fist time. The aromatic series of botrytised wine continues with intense aromas of dried apricot, honey, apricot and peach jam, candied fruit, orange peel, as well as orange blossom and broom. Aromas of tropical fruit can be perceived as well, such as banana, pineapple and litchi.

 During the gustatory analysis, the three wines will be noticed for their common characteristic: sweetness. This taste will be the first one to be perceived and there will be a clear and strong sensation of roundness in the oral cavity, a sensation almost syrupy without being sickly. In all three wines the correspondence to the nose will be truly convincing: the pleasing aromas perceived to the nose have now become flavors. Then it will be evaluated the balance and the relations among alcohol, sugar and acidity: despite the fact sweetness will be the main gustatory characteristic of the three wines, particular attention will be paid to the role played by the pseudo caloric sensation of alcohol that will tend to diminish its perception, as well as acidity, and each one of these wines has a different quantity of acid, that will have the function of balancing sweetness. The most surprising characteristic of the three wine will probably be their taste olfactory persistence, also known as PAI (Intense Aromatic Persistence). Flavors and tastes will be clearly perceivable even after having swallowed the wine and they will even continue to be perceivable after a truly unusual length of time, not common for other wines, often measurable in minutes instead of seconds.