Winemaking
The wine production (including winemaking, vinification or vinification ) refers to the production of the alcoholic beverage wine from crushed grapes or grape must . It can be divided into white wine production and red wine production according to the partly different processes.
White winemaking
Today, white wine grapes are usually processed in a largely reductive state and fermented and matured into white wine . The individual manufacturing stages are divided into:
Mashing
Traditionally, the grapes are destemmed (destemmed, destemming ), that is, the berries are separated from their stems by machine or by hand. Then the berries are crushed in a grinder so that a thick mixture of pulp, grape seeds, peel and juice is created, the mash . The mash is now left to its own devices for a few hours in order to extract aroma precursors, flavorings, phenols and other soluble substances from the berries into the juice. This maceration time releases substances that affect the sensory properties, structure and shelf life of the later wine. In addition, the pressability is improved, as enzymes are released after two to three hours that break down the pectins of the berry skin and pulp. The standing time of the white grape mash depends on the quality of the grapes and is relatively short, usually one to six hours. Wineries that specialize in complex and storable white wines often work with maceration.
Pressing
The mash is then pressed in a wine press (also known as a “wine press”). In this way, the grape residues ( pomace ) are separated from the sweet grape juice ( must ). 100 liters of mash are obtained from around 115 kilograms of grapes, from which around 65 to 85 liters of must can be obtained. Today pneumatic presses are generally used for white wine, in which an air bag is inflated in the middle of the press cylinder. Gentle pressing is important so that no bitter substances get into the wine. These would be released by crushing the kernels.
In recent years, whole bunch pressing has also become established in many wineries , whereby the mashing and the maceration time are omitted, since the grapes are put directly into the press. With this gentle form of grape pressing, the extract content of the must is reduced because fewer substances are released from the berries. One advantage is that the must is of high quality (fewer phenols with more acidity and higher fruitiness). This process is particularly suitable for very ripe grapes and is increasingly used in the production of finely structured Riesling , white quality sparkling wine from dark grapes or sweet wines such as Sauternes .
The solid components of the berries (skins, seeds, stalks) that remain in the winepress after pressing are called grains or marc. The spent grain has previously poured with water and pressed again, thus obtaining the so called wine marc (wine marc), as the home drink ( " house drink was prepared") for workers and the family of the winemaker. Today this process is banned in EU countries and in most other countries by the wine law. The pomace is, however, processed to a small extent into spent grains or pomace schnapps ( Marc , Grappa ).
Because spent grains contain a lot of minerals, vitamins and fiber, it is suitable as animal feed. However, it does not keep very long, as fermentation starts relatively quickly even with the marc. In addition, animal husbandry is no longer very widespread in many wine-growing areas. As a result, the spent grain is usually brought into the vineyard as fertilizer. In some areas it is also mixed with bread dough, which makes grain bread .
Pomace can be dried industrially and then used as solid fuel in suitable facilities for energy conversion.
enrichment
In many countries, the wine law allows the must to be enriched , that is, sugar or concentrated grape juice (RTK) is added so that the wine reaches a higher alcohol content.
Sulphurization
The must obtained is then sulphurised. This is done by introducing sulphurous acid or sulfur dioxide into the must. Alternatively, this can also be done by adding potassium disulfite (also called potassium pyrosulfite). The sulphurization should
a) prevent oxidation, that is:
- Protect wine ingredients that are sensitive to oxidation
- Prevent enzymatic browning
- prevent the development of an air, sherry or age tone
b) protect against microbial spoilage, that is:
- inhibit the growth of undesirable microorganisms such as "wild" yeast, lactic acid and acetic acid bacteria .
The correct dosage of the additives is of great importance for the course of fermentation and maturation and thus also decisive for the quality of the wine. Finished wines should contain around 40 milligrams of sulfur dioxide per liter, although higher limit values are permitted for certain grape varieties and production processes. Overdosing is not without problems, as heavily sulphurized wines can on the one hand lead to indigestion with signs such as headache and stomach and digestive complaints and on the other hand, over-sulphurisation can cause an annoying sulfur odor or, in higher concentrations, directly affect the taste of the wine. In the latter case, it is said that the wine tastes “small”, that is, the excessive sulfur content changes the taste profile of the wine. In addition, overdosed sulphurous acid in wine has a bleaching effect and can therefore cause a visible loss of color, especially in the case of less color-intensive red wine varieties.
It is of particular importance that sulphurous acid occurs in wine after a short time, both in free and bound form. The bound form is useless for the preservative effect of the sulphurisation. Limit values and the harmful effects of sulphurous acid, however, relate to the total value. The aim here is therefore to keep the proportion of bound sulphurous acid low.
This is best achieved when a wine is fully fermented and the sulfur dioxide is introduced into the cellar-light wine (separated from the yeast). However, a wine can already spoil during fermentation if the grapes contain too many undesirable microorganisms or if the hygienic conditions for winemaking are not optimal. The growth of germs can be reduced by adding sulfur. In this case, the risk of an appropriately dosed sulfurization can be weighed against the risk of premature spoilage. Here too, as with the entire manufacturing process, the principle of good cellar practice applies, which prescribes the appropriate use of sulphurisation.
fermentation
Fermentation then takes place. It runs in barrels, metal tanks or rectangular containers made of stainless steel that are sealed with fermentation caps such as the fermentation tube . By exogenous Saccharomyces on the grapes or in the basement of the fermentation process can be brought automatically into gear, but are often special yeasts added.
The main fermentation lasts six to eight days. During this time, the sugar contained in the must is converted into alcohol . During fermentation, the liquid can heat up to 30 ° C. As a result, the yeasts multiply faster and the wine ferments faster. Most winemakers want to prevent this and control the temperature of the fermentation liquid to achieve temperature controlled fermentation. Most winemakers ferment white wine at 15 to 18 ° C and red wines at 22 to 25 ° C. The longer the fermentation lasts, the fresher and leaner the wine appears; conversely, the wine becomes stronger if it is fermented at a higher temperature. This is due to the tannins and aromas, the carriers of the flavors, which react more with other substances at higher temperatures and thus contribute to a stronger taste in the wine.
After the fermentation process, most wines reach between 8 and 13 percent alcohol by volume ; there are exceptions, up to 17 percent alcohol can be achieved through fermentation with certain yeast strains. In addition to alcohol, there are around 400 other compounds that affect the smell and taste of wine. As long as the must is in the fermentation process, it is also known as Federweißer or Federroter (Roter Rauscher) in German-speaking countries or as Sturm in Austria. When the must is completely fermented, you get “dry” wine. If fermentation is interrupted prematurely ( fermentation interruption ), depending on the amount of unfermented residual sugar, “semi-dry”, “sweet” or sweet wine is obtained. At low temperatures, fermentation can stall on its own. Vintners in the northern border areas can often control this process quite easily by opening an outside cellar door in cold weather.
Racking
Fermentation is usually completed in Central Europe around the end of December. The dead yeasts then slowly sink to the bottom. Sometimes a secondary fermentation, the malolactic fermentation, occurs spontaneously or under the control of the cellar master . It is also known as malolactic acid degradation, as certain lactic acid bacteria convert the malic acid in wine into milder lactic acid (also deliberately initiated by the addition of Oenococcus oeni ). White wines from cool growing areas contain more malic acid, from warm growing areas less. Most German white wine producers reject malolactic fermentation. Acid can generate a lively and refreshing taste impression in white wines.
Now is tapped (see racking (wine) ) , that is, the deposited at the bottom of the pack yeast ( lees ) is removed and the wine is stored in other containers. Most of the time, the wine is sucked up from above. The remaining yeast can be pressed out and the resulting yeast wine can be distilled to make yeast brandy .
maturation
The young wine rests for the next three to six months in steel tanks, wooden barrels or, rarely, in glass and plastic containers. During this time, the fine yeast, i.e. suspended parts of the yeast that have not sunk, continue to ferment and break down the proteins still contained in the wine. The salts of tartaric acid ( tartar ) are deposited on the bottom and walls of the container at this time. The young wine is already drinkable, but depending on the requirements, further decanting, filtration and further treatments follow. Sometimes the wine is " fined ", whereby any remaining cloud substances are bound and filtered out.
Some strong white wines are sometimes aged in barrique barrels for a few months to several years . The wine takes over the taste and color of the wood. The age of the barrel, i.e. how often it has been used, plays an important role. With new barrels, the wood tone is often very dominant and the wine taste takes a back seat. If the barrels are too old, the wine sometimes looks musty and stale. Many winemakers achieve the best results by aging in old and new barrels and later blending the contents. During the aging process in the barrique, white wines are regularly stirred ( batonnage ). In this way, the yeast deposited on the bottom of the barrel should be added to the wine as a suspension ; this gives it more volume and structure.
storage
Most white wines can be stored for up to four years without being exposed to major negative changes. Some white wines - especially sweet wines that have been made through noble rot - can withstand 10 to 20 years, some even over 200 years and are still drinkable.
Several factors are decisive for the long-term storage life. Wine should generally be stored protected from light, at moderate, constant temperatures ("cellar temperature") and to protect it from oxidation by reduction , largely in the absence of air. This can be done either in bungee barrels or in bottles, bottles being stored horizontally in order to keep the cork moist, as a drying cork becomes increasingly air-permeable over time. In addition, the sterility and care in the production process have a great influence, as they can minimize the content of microorganisms in the finished wine from the outset and thus it remains "stable". Furthermore, the fruit acids contained in wine , such as tartaric and malic acid, as well as alcohol and tannins, have an antimicrobial effect. Sulfurization also increases the shelf life.
Red wine production
The most important difference to white wine is the sequence of the work steps. If necessary, it is not the must but the mash that is enriched (added sugar) and fermented. This happens because almost all of the coloring is in the skins of the grapes. These dyes are released from the red fruit peel by the alcohol produced. It is only pressed after fermentation. This results in the following sequence, whereby the functions of the individual work steps are the same as those of white wine making:
Mashing
After the harvest and the grape selection, mashing is the next step in the process of producing wine. Mashing means tearing and breaking the berry skins, releasing the grape juice and mixing the solid and liquid components of the grapes. The cold maceration process has become established for high-quality red wines in recent years . The mash is cooled down considerably and the start of fermentation is delayed by a few days. This enables the extraction of finer fruit flavors.
A special process for making red wine is carbonic acid maceration. In this process, the berries are largely not crushed. The result is very fruity wines that can be drunk young. Wines to be drunk young mean that they do not have to age for long.
fermentation
The fermentation of the mash usually starts by itself, as yeasts are omnipresent to initiate fermentation. Often, however, the winemaker does not simply want to let any random yeast start fermenting and instead adds specially selected yeasts, so-called pure yeasts, to the mash. These yeasts should ensure reproducible, good fermentation properties. However, the use of cultured yeasts is also criticized, as a trend towards impoverishment through standardization or unification cannot be completely denied.
In red wine production , the mash remains in places for weeks; the fermentation process takes place together with the liquid and solid components of the grape. The fermentation containers used for this are nowadays often set up so that the process heat generated during fermentation can be removed in a controlled manner by means of cooling coils . The long stay on the mash serves for the intensive extraction of the colorings from the berry skins and the extraction of tannins . Tannins are an important component for the structure of red wine and largely determine its shelf life. During the mash fermentation, most of the solid components in the fermentation vats tend to float, as they are specifically lighter than the must due to the adhering fermentation carbonic acid. Either this “marc cap” is occasionally submerged (by hand or by means of compressed air-operated sieves), or the young wine that is produced is drawn off from below and pumped back over the marc cap from above ( reassembly ).
Which material the winemaker prefers for the fermentation tank is a matter of taste. Traditional wooden and concrete containers are more difficult to cool, but keep the temperature once reached more stable. The stainless steel containers, which have appeared since the mid-1960s , are easier to cool, but are also more sensitive to changes in the basement temperature. Once a decision has been made, the winemaker is typically bound for a long time, not only for reasons of cost, but also for reasons of weight: Concrete tanks weigh several tons.
How long the red wine ferments on the mash depends primarily on the fermentation temperature. The lower it is, the slower the mash ferments. Conversely, the higher it is, the faster the fermentation takes place. Simple red wines such as Valpolicella or Beaujolais ferment on the mash for about four days. Red wines with a higher content, such as Alsatian Pinot Noir or Badischer Spätburgunder, come into contact with the peel for about eight days. For heavier red wines, a mash fermentation of around 15 days is often carried out. Traditional Barolos or Cabernet Sauvignons can be left on the mash for up to four weeks.
Press
Pressing is the separation of the mash into a solid and a liquid phase. In the past, this was done with basket presses, which were designed as vertical screw presses in wood. In recent times, horizontal, pneumatically operated tank presses made of stainless steel have been used, which are offered either as so-called "open presses" or as "closed presses" (presses under the exclusion of air using inert gas).
Most of the red wine flows off without pressing. The wine obtained by pressing is called pressed wine and contains about four times as many tannins as the first wine. In the further expansion, the winemaker decides to what extent to add the pressed wine again.
expansion
The fermented wine is stored in barrels, tanks or fermentation vessels in the cellar and matured over several weeks or years. The longer the expansion takes place, the more costly it is. Occasionally the expansion in clay amphorae (in Georgia: Quevri ), which was prevalent in antiquity, can also be found.
High-quality, strong wines sometimes mature in barrique barrels for a few months to several years . Depending on how often a barrel has already been used, the wine absorbs the taste, tanning and coloring of the wood. The choice of a wooden barrel (type of wood, barrel size) has an impact on whether the wine experiences an oxidative or reductive character during aging . In addition, the barrel has an influence on the structure and thus also on the aroma of a wine. (→ Aromas in the wine ) The age of the barrel, i.e. how often it has been used before, plays an important role. With new barrels, the wood tone can sometimes be very strong. Many winemakers achieve good results by maturing the wine in old and new barrels as well as in tanks and later blending the differently matured batches.
The racking takes place at certain time intervals in order to free the wine from the sediment that collects in the containers below. It can also be pumped to other containers and filtered if necessary. Most wines are fined and filtered before bottling .
maturation
Most red wines can later be stored in the cellar for up to four years without being exposed to major negative changes. Some red wines can survive 10 to 20 years, some even more than 200 years and are still drinkable. The composition of the grape varieties is essential for the chance of aging, as is the quality of the work in the vineyard and cellar. Red wine that has a long shelf life is usually the Bordeaux wine , which from very good years and from good wineries should often be stored for ten or more years in order to achieve the peak of drinking pleasure. There are also other long-lived red wines besides Bordeaux ( Burgundy and Barolos ), but their shelf life and maturation times are usually much more difficult to estimate. There are Bordeaux vintages whose highest quality specimens are over 30 years old and in 2006 still had not reached the peak of their maturation (1975, see vintage ). At the other end of the spectrum there are red wines that promise reliable drinking pleasure only in the first two or three years after the harvest; thereafter the risk of default increases rapidly.
Rosé wines
Real rosé wines are made from red wine grapes, the process is similar to white wine production, but the mash is allowed to rest and ferment for a few hours so that some of the coloring matter is removed from the skins of the red wine grapes. In some cases, rosé wine is also obtained by removing around 10 to 15 percent of the volume from red wine mash after a few hours or days ( Saignée method). The rosé wine obtained in this way is mostly deeper in color and stronger, but less fruity. In the so-called Rotling , white and red wine grapes are mashed together or the already finished mashes are blended . However, the pressing must be done together.
Fruit wines (also fruit wines)
The above description was based on the traditional wine base, the grapes. In Germany, especially in the regions north of the Main, other types of fruit have also established themselves for fermentation. In contrast to grapes, many types of fruit require a little help during fermentation. Since they do not have enough fructose, an appropriate amount of sugar is added to the wine. In some fruits (bananas, strawberries) the acidity is too low. This can be increased during fermentation by adding 80 percent lactic acid .
This procedure is also common in other countries.
Fruit wines are not to be regarded as wine within the meaning of the Wine Act.
See also
Jargon
The German-language specialist wine production terminology is recorded in the dictionary of German wine- growing language and the word atlas of continental Germanic wine- growing terminology .
literature
- Robert Steidl: Cellar economy. 7th updated edition. Österreichischer Agrarverlag, Vienna 2010, ISBN 978-3704016997
- Helmut Hans Dittrich, Manfred Großmann: microbiology of wine. 3. Edition. Ulmer, Stuttgart 2005, ISBN 3-8001-4470-0
- Jens Priewe: Wine. The new big school . Zabert Sandmann, Munich 2005, ISBN 3-89883-137-X .
- Gerhard Troost : Technology of Wine . 6th edition. Ulmer, Stuttgart 1988, ISBN 3-8001-5816-7 (standard work).
Web links
- This is how wine is made! Production in the vineyard and cellar. Published by Winety.com
- Gleanings: Designer Wine from the Refinery - The Winemaker's Tricks
- Dictionary of the German-speaking winegrowers' language with online version. Published by the Academy of Sciences and Literature Mainz.
- Wine book for winemaking from the 17th century as a digital copy from the Bamberg State Library
Individual evidence
- ↑ Jancis Robinson : The Oxford Wine Lexicon. 2nd Edition. Hallwag, Munich 2003, ISBN 3-7742-0914-6 , p. 841 f.
- ↑ Jancis Robinson: The Oxford Wine Lexicon. 2nd Edition. Hallwag, Munich 2003, ISBN 3-7742-0914-6 , p. 275.
- ^ A b Robert Steidl: Cellar economy. 7th edition. Österreichischer Agrarverlag, Vienna 2010.
- ↑ Jancis Robinson: The Oxford Wine Lexicon. Hallwag Verlag, Munich 2003, p. 48.
- ↑ Horst Dippel : The wine dictionary. 4th edition. Fischer, Frankfurt am Main 2000, p. 32.
- ↑ Jancis Robinson: The Oxford Wine Lexicon. Hallwag Verlag, Munich 2003, pp. 241–246.