Incombustible, colorless and odorless, acidic gas (including carbon dioxide) with the empirical formula CO 2. Colloquially, carbon dioxide is very often mistakenly called carbonic acid designated. The gas is created in all combustion processes and also in the breathing of animal and human beings. It also occurs in volcanic rocks and at great depths. In the atmosphere it only makes up a small fraction of 0.039 percent by volume, but this tiny amount is essential for all life because it is from the plants in the photosynthesis needed and the oxygen is formed. Since industrialization, the share has increased by around 25% due to the so-called greenhouse effect, which is directly related to the climate Change stands. The proportion is larger (probably due to the larger land mass) in the northern hemisphere.
Carbon dioxide dissolves in liquids as well as in wine depending on pressure and temperature. In the solution, reaction with water to a minimum of only 0.2% also produces carbonic acid. By far the largest part (over 99%) is the carbon dioxide dissolved in the wine (which does not yet produce any carbon dioxide), which is summarized with the actual carbon dioxide as "free carbon dioxide". As the vine is made from carbon dioxide and water sugar in the grapes educated. In the fermentation then the sugar in carbon dioxide and alcohol converted. At 1.98 g / l, carbon dioxide is around 1.5 times heavier than air. That is why there is a risk of suffocation in the fermentation cellar if the gas is not discharged using exhaust doors. The formation of carbon dioxide is caused by lees promoted, as well as by expansion in stainless steel tank favored. Still wines may contain a maximum of 3 g / l (corresponds to 1 bar at 20 ° C). A sparkling wine must have at least 3.5 bar overpressure (corresponds to 6.5 g / l at 20 ° C). The recommended or prescribed amounts are (measured at 20 ° C):
type of wine
Rec / vorg
Carbon dioxide in g / l
|White wine||recommended||1.2 to 1.5|
|rosé wine||recommended||1.0 to 1.5|
|fresh red wine||recommended||0.5 to 0.7|
|strong red wine||recommended||<0.6|
|Perlwein||required||3 (1 bar) to 5.1 (2.5 bar)|
|sparkling wine (see also under sparkling wine )||required||6.5 (3.5 bar) to 9.8 (6 bar)|
Carbon dioxide is not one of them acids, but reinforces one sour Sensation and has great influence on the sensory Characteristics. in the White wine and rosé wine it looks refreshing and lively. If the concentration is too low, especially in white wine, a hollow (Empty) taste impression. in the red wine however, it is usually perceived as annoying because it is the astringent Effect of tannins increased, thereby sharp Taste impression arises and aromas are masked (covered). With red wines such as for quick enjoyment Beaujolais Nouveau arises from the type of winemaking a higher proportion and is also desired there. At the sparkling wine a minimum quantity is prescribed by law, with particularly fine bubbles or high Perlfähigkeit are important quality criteria.
Refreshing is useful for white wine below 0.7 g / l and for red wine below 0.4 g / l. In order to achieve a desired carbon dioxide content in the wine, this must be measured regularly and regulated if necessary. An increase or decrease takes place by means of a gassing valve. There are various methods for pressure measurement. Of the OIV becomes titration recommended, which, however, requires appropriate laboratory equipment. The simplest method at Stillwein is the Veitshöchheimer shaking cylinder, which consists of a riser pipe, thermometer and conversion table. In the closed measuring cylinder, 100 ml of wine "shakes" the carbon dioxide and, depending on the content, displaces a corresponding amount of wine from the cylinder. Special measuring devices are required for sparkling wine. The pressure in the bottle is measured using aphrometer detected.
There is also further use or use of carbon dioxide in winemaking. With the so-called impregnation will Perlwein generated. When using a maceration in red wine making, the empty space of the container is filled to the extraction intensify the dyes and tannins (see also under Maceration carbonique ). Through air (oxygen) displacement in containers and bottles, a oxidation protection reached. Furthermore, carbon dioxide is removed with the help of a candle frit to remove off-flavors such as light sulfurous off (Sulfur baker) used. And last but not least, carbon dioxide also serves for the neutralization of alkaline cleaning solutions (such as those used for cleaning bottles and containers are used) with regard to basement hygiene. See a list of all wine ingredients below total extract,