Screening: The grapes are sometimes harvested with leaves and unripe or rotting grapes, especially in bad years, and more serious wineries will screen the grapes before vinification.
Breaking the skins: Since the skins contain important components such as tannins, red pigments and aromas, they must be broken and squeezed out of the pulp before fermentation, especially in red wines, to allow the juice to come into contact with the skins and to allow these substances to dissolve into the wine. The breaking of the skins must be carried out to the right degree in order to avoid the release of oils and tannins from the stalks and seeds, which can affect the quality of the wine.
De-stemming: the tannins in the stems of the grapes are highly astringent and often have a pungent, grassy flavor when they are not fully ripe, so they must be completely removed. Wine with too much tannin will taste hard and bitter, leaving a dry sensation in the mouth. The de-stemming step cannot be omitted in the production of red wines because the pressed grapes, also known as grape pulp, as we will see later, may have been fermented before the juice was pressed. In the case of thin wines, on the other hand, de-stemming is not necessary, and the skins and stems are left to ferment together for a short period of time. In the case of white wines, de-stemming may also be omitted, especially in the case of Lilium, whose heavily lignified stalks release very little tannin. It is the destemmer that separates the berries from the stalks.
Pressing: All white wines are pressed before fermentation (red wines are pressed after fermentation), sometimes without going through the destemming process. Special care must be taken not to over-pressurize the juice in order to avoid a bitter stemmy taste. Traditionally, vertical presses are used, and airbag presses are used to moderate the pressure.
Both red and white wines, irrespective of the type of wine, must undergo a procedure that separates the solid and liquid components of the grape pulp, which is known as "pressing" in the specialized terminology of wine. This is called "must" in the specialized terminology for wine. After the must is pressed, the raw material for winemaking, grape juice, is obtained. The sugar content varies depending on the variety and maturity of the grapes harvested.
The oldest method of juicing is to step on the grapes with bare feet. This is not an ineffective method, but it is less economical and less hygienic. In some countries of the South, traditional presses can still be found, mainly in small wine stores. Apart from this, the vast majority of wine farmers have long since generalized the use of machines and equipment in large plants. The most common case is the use of air compressors to extract the must. In large presses, even 50 tons of grapes per hour can be processed.
The next step is to measure the percentage of sugar in the juice using a special scale for grape juice. If the index is lower than the legal minimum, it is necessary to sweeten it by adding sucrose to the must, or in Italy and some Balkan countries, by adding sugar-rich concentrated grape juice. The maximum limits of sweetening measures are expressly set by law. In warmer regions, such as Appellation C, the amount of sugar that can be allowed is lower than in the colder climate of Appellation A. The maximum amount of sugar that can be added to the wine in the warmer regions of Appellation C is lower than in the colder climate of Appellation A.
In German-speaking countries, sweetened grape juice can only produce average quality wines, everyday table wines and regional table wines. Conversely, in France, sweetening is only permitted for higher quality wines.
The sweetening procedure is carried out before fermentation, as it takes part in the fermentation. Contrary to popular belief, the addition of sugar does not sweeten the wine, but increases its alcoholic strength, as precisely stated in the article "Sweetening", which has been included in the German Oenological Code since 1971.
Before formal fermentation, a must settling step is sometimes added, as appropriate, to allow the must to be filtered out of any traces of juice or sediment.
Fermentation
As we know from the definitions in the Wine Code, wine is the product of fermentation. Fermentation plays a very important role in the winemaking process.
What is fermentation and how does it work? Fermentation is a chemical process that takes place through the yeast. Through this chemical process, the sugars contained in the grapes are gradually transformed into alcohol and carbon dioxide. As a result, during the fermentation process, the sugar content becomes less and less and the alcohol content becomes more and more alcoholic. The fermentation process continues until all the sugar has been converted into alcohol. In this case, the result is a fully fermented, unsweetened wine, which of course has a relatively high alcohol content. If, on the other hand, the wine contains more sugar than the yeast can handle, as in the case of some late-picked grapes, the fermentation process ends prematurely, and the result is a wine with a sweeter flavor and a lower alcohol content.
The fermentation process depends on a number of natural factors, including the grape variety and the ripeness, or sugar content, of the berries. In many countries, winemakers no longer rely on the natural yeasts contained in the skins of the grapes to carry out the fermentation, but add artificial yeasts to the must so that the fermentation process can be optimized. In addition, the winemaker can also use his skill to influence or "guide" the fermentation process by adding cooling to slow it down, by stirring or adding yeast to make it faster, by stopping the fermentation with alcohol, or even by adding re-fermentation agents to cause a second fermentation.
Slow fermentation produces wines that are aromatic and nuanced in flavor. The process of arrested fermentation produces sweet wines that are suitable for desserts. Sparkling wines are produced through the process of secondary fermentation. Many specialty wines are made using special fermentation methods.
Although this is the first step, the winemaker's work is still far from done! The new wines are often unruly and raw, and it is only through careful attention that they can develop into wines that will make wine lovers' hearts beat faster. Carbon dioxide - sedimentation - filtration
If you want to preserve the fruitiness and freshness of the wine, it is necessary to add carbon dioxide immediately after the fermentation, which prevents the oxidizing effects caused by the contact of oxygen in the air. This is not a new invention in our chemical-loving age; it has been known since Roman times that unsulphured wines quickly lose their flavor and become difficult to condone.
Here, sulfur dioxide is added to the wine in the form of sulfuric acid. This sulphuric acid has almost no flavor of its own and is completely harmless to health when used in small doses. The dosage of sulfuric acid is specified in the winemaking laws. The EG countries of the European Union have been aware of this for a long time and have harmonized their laws and regulations with other non-European countries.
Selected grapes and selected dry grapes, compared with other grapes, in the process of adding carbon dioxide must be strengthened treatment, as for fully fermented, not sweet red wine, carbon dioxide can be lighter, because the alcohol, especially tannins, can guarantee a greater capacity for storage. Sulphur has another function: it keeps the empty barrels free of microbes, while maintaining hygiene and cleanliness.