Red wine is the wine for excellence. It is one of the most ancient beverages even produced by the human being, so that its roots are lost in the milleniums. Most likely it was discovered randomly, after a spontaneous fermentation of some vine grapes kept in a container. Since then much has changed in terms of agriculture and technology, but the concept behind its production has always remained the same.
Its name comes - obviusly - from the typical red colour, finding when you observe it backlit or near a white surface. The most typical nuance is ruby red, that becomes purple red in young wines and garnet and orange red in mature wines.
Maceration is the process that gives the wine its typical color: during this phase the must (that is the future wine) is in close contact with the marcs that, depending on the vine variety, releases a certain quantity of colouring substances.
Phases of the red winemaking
Red winemaking is a process composed of a series of mechanical and chemical transformations that starts from the bunch of grapes, as it is on the plant, and reaches the bottle of wine, completed with a label.
To simplify in minimum terms, you can imagine three macro-phases of the transformation during which the material, with the skilful intervention of the wine maker, loses its original appearance and acquires new forms and characteristics: from grape to must, from must to wine.
Destemming / Cruching
Once the grapes are harvested, they are immediately transferred to the cellar where they are subjected to the destemming process. It is a mechanical operation useful to separate the stalks from the berries, before submitting the grapes to the following phases.
This is followed by the pressing, a further mechanical operation, carried out with a special machine (the crushing machine), which causes the berries breack and facilitates the diffusion of the juices in the pulp. Recently it is done softly to avoid letting out the tannin, bitter, from seeds and stalks. It is not unusual to destemm and crush together using special destem-crushing machines.
At the end of these two operations a dense and turbid liquid is obtained, the must, composed of the pulp. the skin and the grape seeds.
Treatments and corrections of the must
The must that comes out from the crushing is a turbid, dense and unstable product. Before procediing with the subsequent fermentation phase, it is possible to intervene with appropriate treatments and corrections.
The treatments are intended to stabilize or enhance some of its characteristtics, without removing or adding anything to the liquid. Among these, clarification and filtration, conducted alone or in combination, are ancient oenological practices that, recently added to the cooling, allow to obtain a greater degree of clarity, without depriving the must of all those substances that will give a certain characterization to the final product.
One of the most known but also controversial treatments is sulfitation, that is the practice that involves the introduction of sulfur dioxide. On the one hand it allows to reduce the instability of the wine, thus avoiding its possible transformations, such as sedimentation, darkening, colour changing (oxidase), mutation of the orgalolectic characteristics (oxidation) and uncontrolled fermentation; on the other hand, it is unpopular bacause, after certain doses, it is harmful.
Corrections, unlike the treatments, compensate for any deficiencies of acids or sugar, often due to adverse climatic trends.
Alcoholic fermentation with maceration
Alcoholic fermentation is the key of winemaking. At this point of the process, after preparatory stages, the must and the marcs are placed inside a large inert container, usually is steel or fiberglass (not wood), where they are added with selected yeast. Thus begins the fermentation process with maceration during which, essentially, the yeast "operates" so that the sugar is transformed into alcohol, carbon dioxide and heat.
Generally a high fermentation temperature does not permit to obtain quality wines (in fact it stimulates the dissolution of the substances contained in the marc and inhibits the action of the yeasts), therefore it is kept between 25 and 30°C - 77 and 86°F - by means of a special cooling system.
During fermentation, the marcs tend to forma a compact layer in the upper part of the container, called hat, preventing a good contact between must and marcs themself. To remedy this, the must is remixed regularly through the processes of punch-down or pump-over.
The punch-down consists in mechanically break of the marcs cap, thus facilitating the contact of the marcs with the must and ensuring an adeguate heat exchange towards outside.
The pump-over (rimontaggio in Italian) consists in taking the must from the bottom of the container and reinserting it in the upper part above the cap. Whit this operation the must is oxygenated, stimulating the work of the yeasts.
At the end of fermentation you proceed with the racking, i.e. the removal of the marc and fermentatin lees (dead yeast cells). The wine that is obtained is called free-press wine (flower wine in Italian).
After extracting the free-press wine, the marcs left inside the fermentation container are collected and dried up by the pressing, an operation that must be carried out delicately. To avoid too strong pressing (which would crash the grape seeds and release un pleasant acid substances), membrane presses are used. The obtained wine in this phase is called first-press wine and, at the discretion of the winemaker, can be combined with the free-press wine or vinified separately.
The pressed marcs are not thrown away, but used for the production of the grappa.
Malolactic fermentation, as realized by the name, is a process that involves two acids, malic acid and lactic acid, but it is not always used in the vinification process. In fact it is an option that the wine maker has in order to characterize more the wine in terms of softnesses, going to smooth too high acidities.
The malic acid is one of the key components that guarantee the acidity to the wine. It comes directly from the grapes and its quantity is related, in addition to the grapes variety, to the weather trend and to the fruit ripening process. Within a certain threshold, it has not unpleasant effects on the flavour profile but, in high concentrations, is produces a bitter and sour taste, similar to the one experienced by eating an immature apple.
The malolactic fermentation activates automatically after alcoholic fermentation (provided that the temperature is between 18 and 20°C - 64 and 68°F - the alcohol content is below 15% and the pH s higher than 4) but it can be further stimulated by introducing certain bacteria into the wine. The main product of the transformation is the lactic acid. This one is less pungent and sour than the malic, so the wine is softer and with more complex tasting profiles.
For this ability to smooth the acidity notes, this kind of transformation is very much used in wines destinated for ageing, both red and white ones. Is is less used, or even avoided, in young wines that must keep certain characteristics of freshness and fragrance.
At the end of the fermentation and racking processes, the wine is still immature to be bottled and placed on the market; therefore it needs a phase of maturation, even short, in order to smooth the hardness and blend itself. This phase can take place in various ways and times, depending on the product you want to achieve.
There are two big categories of container where to carry the wine maturation out:
- steel or fiberglass barrels;
- wood barrels.
The steel or fiberglass barrels are substantially inert, i.e. they do not interact with the liquid, meanwhile the wood barrels are made of organic material, far from being inert. This does not affect the quality of ripening, which is of the same level, but the final organoleptic profile of the wine.
The wood barrels, in turn, have different dimensions and also the woods have unique characteristics. The wood, in contact with the wine, releases additional aromas that are added to the initial bouquet of scents. In this way the wine becomes variegated or even complex, acquiring pleasant spicy, woody, toasted and animal notes.
The duration of the ripening affects the organolectic profile of the wine. It the ripening takes place in steel or fiberglass barrels, therefore inert, it allows the wine to blend and define its character.
If the ripening takes place in wood barrels, further to what happens for inert barrels, its duration directly influences the amount of substances that are released from the wood, then the intensity of the final olfactory profile.
Once riped, the wine is ready to be bottled. Since the bottle, when you close it, represents a point of not return, it is important to be sure of both quality of the wine and the final image that it will have once put on the market. So, the choice of the cap and the shape of the bottle, even thought it may seem trivial is an important step that should not be overlooked.
Refinement, also called cellaring, is a kind of further ripening, a period of more or less long time diring which the wine rests inside the bottle. It can be conducted in the cellar or it can directly made by the consumer, giving up the temptation to uncork a just bought bottle. In this period the wine is further transformed: it improves its characteristics, smoothing out the astringent notes and stimulating the birth of new aromas. It can last from few months to years, but it depends a lot on the type of grapes used and the winemaking process.