Generality
In its common meaning, the term "must" identifies the liquid obtained from the pressing of grapes.
- cooked must is necessary for the coloring of some particular wines;
- the siphon is necessary to raise the final alcohol content (see the article: Marsala);
- the concentrated must is industrially produced and has a high sugar content (up to 50-70%); it is useful for correcting slightly sweet musts.
- the sweet filtered must is deprived of nitrogenous substances and is therefore BLOCKED by fermentation; it is used to carry out cuts and refermentations.
- in the still must fermentation is blocked by the massive addition of sulfur dioxide; this, before use, must be eliminated from the product.
Other musts, different from the fresh one and from those just described, are: the partially fermented must (having an alcohol content between 1-60% of the potential) and the concentrated - rectified must (more similar to grape sugar than to normal concentrate).
The must, depending on the type of grape or blend and the winemaking technique, can give rise to white, black or rosé wines. Only later, depending on the time and bottling technique, can the drink acquire firmness or effervescence.
Grape must must not be confused with grape juice
Composition of the must
The wort has a watery consistency but also contains a solid portion. The liquids, of course, derive from the water-soluble portion of the berries, while the solids are composed of more or less important portions of wood (petioles and, sometimes, stalks / stalks), skins and seeds.
From a chemical point of view (considering the appropriate differences between grapes and blends), the must contains 70-80% of water, while the remaining 20-30% is represented by: simple sugars, acids, mineral salts, nitrogenous substances (inorganic and protein), phenolic substances (pigments and tannins), pectic substances (pectins and relative hydrolytic residues), vitamins, crushing residues and, last but not least, yeasts (responsible for wine fermentation). In the table below, taken from the text "How to Make Wine", by Lucio Bussi, we find summarized the main components of the must ordered by QUANTITATIVE importance.
Functions of the Various Components of the Must
Water is the main element of the must and, since it is an essentially water-soluble solution (with the exception of crushing residues and a few other elements), its function is mainly that of a solvent; from an oenological point of view, the quantity of water mainly affects the relationship with sugars, and therefore on the definitive alcohol content.
Simple carbohydrates are predominantly made up of fructose. This, which in the right microbial transformation is converted into ethyl alcohol, must not be too scarce, but not too abundant. In both cases (and in compliance with the specification), the must must be corrected from before fermentation to reach the right sugar level.
mineral salts (potassium and calcium, which act as alkaline bases), can crystallize forming salts such as cream of tartar (or potassium acid tartrate) and calcium tartrate; these, being not very soluble, precipitate and are deposited, while other salts such as that of malic acid and neutral tartrate dissolve more easily.
The coloring and tannic phenolic substances (polyphenols) are present in proportion to the quantity of pomace and their maceration time in the must (the pomace is the solid part composed of skins, seeds and other woody components). More precisely, the pigments are mostly present in the skins, while tannins abound in the seeds and stalks / stalks. The pigments of the must determine the color of the product, while the tannins constitute the body of the finished wine (tannic or astringent action).
More than from the technical or oenological one, vitamins take on a more relevant role from a nutritional point of view. Among these, C, certain provitamins A and some of the B group stand out. As regards the minerals (ions and salts), they are more concentrated: potassium, calcium, magnesium, sodium, phosphates, sulphates , chlorides, iron and copper. The latter, in addition to enriching the nutritional profile of the must, regulate fermentation and influence the sapidity and clarity of the wine.
The nitrogenous substances are responsible for the development of yeasts useful for fermentation, during which they are converted into aromatic substances (higher alcohols) necessary for the structuring of the "final aroma. On the other hand, an excess of nitrogenous substances in the must can cause instability. and the turbidity of the finished product.
The Must ... Can You Eat It?
As has been pointed out, must is an intermediate product of wine.
However, a fresh, filtered and pasteurized must, obviously not at all or slightly fermented, can be used for the production of a particularly pleasant sweet food.
Some people also consume it liquid, fresh and raw, but all this is at the "gastro-intestinal" risk and danger of those who take it! It is in fact a drink potentially rich in yeasts which, if taken in significant quantities, can give rise to symptoms such as: bloating, abdominal tension, flatulence and diarrhea.
As for the must-based dessert, it is the well-known "grape pudding" or "grape must sugoli". This food essentially contains carbohydrates, is almost completely devoid of proteins, lipids and fibers and has a variable caloric content depending on the grapes and the added sugar; in this regard, in principle, also taking into account the flour added as a binder, the caloric intake of the sugoli should not be too distant from the 100kcal / 100g.
For more details, see Alice's video recipe: Grape Pudding - Sugoli with Grape Must.
Grape pudding - Sugoli with grape must
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Bibliography:
- How to make wine - Lucio Bussi - Demeter - pag. 40:42.
