Designation (also pressing) for both the pressing process grapes, as well as for the necessary mechanical devices. Presses were made in the early antiquity uses what finds of artifacts from several thousand years old in many old wine-growing areas prove. Among other things, the Roman writer reports Cato the Elder (234-149 BC) about it in his works. Pressing is a crucial step in the winemaking, As a rule, only healthy and physiologically mature Grapes go to processing, which is done by appropriate preparatory work such as selective vintage is accomplished. Depending on the type of wine, a decision must be made whether to press before stemming (De-stalking, rebeling), that means whether the grape skeleton should be removed. When pressing the grape excreted from the grapes by mechanical pressure. Depending on the type of wine, it is separated from the solid components and then further processed, especially with the White wine, where pressing is usually the first step. In the Red wine production this becomes only after the classic maceration carried out.
If the combs are pressed together, they give tannins (Tannins) and pigments (Coloring), which may be desirable for grapes with a strong fruit taste or for red wine production, for example, through technology Maceration carbonique is common. The grapes should be processed as gently as possible by minimizing mechanical influence in order to avoid the undesirable effects in white wine making proportion of turbid (the smallest suspended matter from berry skins and pulp) and the tannin content in the must to keep as low as possible. Modern cellar technology therefore tries to use natural gravity to move grapes and must instead of pumping. Each pumping process increases the amount of turbidity up to 1%. Pneumatic tank presses are the most gentle in this regard.
The use of the latest pneumatic presses and the frequent whole grape pressing process intact grapes, since the combs are not squeezed by the gentle pressing process and there is no risk of too much tannins in the must. Depending on the variant, the grapes (with or without combs) are then squeezed or ground, the berries broken up and the juice leakage made easier. The desired intensity can be set variably. It is an ancient form of squeezing pounding of grapes with bare feet in a container. Occasionally, this is still common today, especially in southern countries, for example in the manufacture of port wine, The result of stripping and squeezing is called a mash. When making red wine now without pressing maceration a, the white wine is now pressed. For an optimal course of the fermentation must have a corresponding must treatment respectively.
The mechanical device required for pressing is referred to as a press or press. From the pressing direction of movement forth a distinction between conventional vertical presses and the usual in newer systems horizontal presses. One of the oldest forms is that used by the Romans Torggel (Torkel), which was in use until the Middle Ages. For centuries the very similar tree presses were used , which today can only be admired as exhibits in many old cellars. A long plate called a tree is used to press a massive plate onto the grapes or the mash in a basket. The must runs through the slits of vertically arranged wooden slats fixed by tires. There are different variants in detail, the principle of operation is as follows:
With the so-called basket presses pressure on the plate is accomplished with a rotating spindle either manually or mechanically. The disadvantage is the relatively small filling quantity, but above all the strong one oxidation and the big problems or effort involved in keeping them clean. The advantage, however, is the relatively low, very slow, gentle pressing pressure. In the Champagne For some houses, special basket presses are therefore traditionally still mandatory for the production of the best champagne qualities.
Today horizontal presses are mostly used (especially in larger companies). With the screw press, mash is constantly filled in at one end, the juice flows through sieve walls, and the squeezed pomace comes out at the other end. This is used in large cellars, especially for bulk wines, because it achieves a high must yield of up to 85% corresponding to lower quality. Other conventional types spindle, screw or toggle presses. In these, a movable plate in the basket is pressed against a fixed end plate or two movable plates move towards each other. These systems, which operate on the hydraulic principle, are the most frequently used presses today.
In the pneumatic hose press, a long press hose inside a container is inflated, thereby pressing the mash against the walls. Since there is a much higher pressing area, the berries are treated more gently and fewer are obtained tannins (Tannins) in the must. These presses combine the advantage of the tree press (low pressure) with also low oxidation and germ-free keeping. In addition, they can be loaded with variable quantities. A further development is the pneumatic tank press . These can also be used inert gas (Shielding gas) to be filled oxygen keep. There are also versions with a perforated outer jacket that are particularly suitable for white wine.
Whole grape pressing is a pressing process in the production of White wine and sparkling wine basic wine, It only came into use worldwide with the spread of pneumatic presses or tank presses. The whole grapes are intact without prior stemming or squeezed. A stage of mashing is eliminated. This is traditionally used in the manufacture of champagne used because in this case the blue grapes have no colorants and none tannins may give to the must. The must obtained in this way results in a delicately aromatic, finely fruity and varietal Wine with a slightly higher acidity. However, the must yield is up to 10% lower.
Due to the large pressing surface and the resulting low pressure, no parts of the bellows (berry skin) get into the must, which contains aromas and flavors, even with white grapes. It must therefore be accepted that the total extract is reduced, which can lead to weak expressions. To prevent this, sometimes only a part of the grapes is processed in this way. The process requires years of experience. In the manufacture of champagne and Crémant it is mandatory.
In general, 1,000 kilograms of grapes provide about 750 to 800 liters of grape must, depending on vine, the grape ripeness, the vintage and press technology. Depending on the desired end product, pressing can take place in several passes, with the must quality steadily decreasing. In between, the press cake is loosened (failed). With conventional mash pressing, one divides into three fractions. The graphic clearly shows which parts of the berries or which of the relevant ingredients of the grapes are affected (see 11.a First pressing, 10.a Second pressing, 12.a Third Pressing):
Even before pressing, the grapes' own weight causes the run juice (Must) from. It makes up about 30 to 50% of the total volume, consists mainly of sugar, must acids and some extract substances, but is low in tannins. The one obtained with low to medium pressure Most Press makes up about 40 to 60%. It is extra rich and contains many tannins and minerals. Flow and press must complement each other and are processed together to produce a strong, tasty wine.
The result of the last pressing processes, which must already be done with relatively high pressure, is called Most funeral, The amount is only 5 to 10%. This must has a multiple of oxidizable sediments. tannins and oxidases on. The latter are responsible for tanning, which is why a sulphurize must be done. If it is added to the main must amount, one is Gelatin treatment required. Mostly, however, it is processed separately and provides a low-quality tannin-rich wine or it is distilled. In the manufacture of champagne only the best press results ( Cuvée and waist ) used.
Complete lists of the numerous vinification measures or cellar techniques, as well as the various types of wine, sparkling wine and distillate regulated by wine law are under the keyword winemaking contain. There is extensive wine law information under the keyword wine law,
Tree press animated: Von Vignes - own work, CC0 , Link
Tank press: From Bauer Karl - own plant, CC BY-SA 3.0 , Link
Tree press Salem: By CrazyD - even photogr. , CC BY-SA 3.0 , link
Basket press: caravan