Inert substances (inert = inactive, uninvolved) are inert substances that do not participate in certain chemical processes because they do not contain oxygen. These are almost all gases (noble gases), except for the very reactive oxygen. In viticulture, these are nitrogen and carbon dioxide, which are often used as protective gases against undesired oxidation in wine containers. This prevents, for example, the wine from becoming chalky (wine defect). So-called inert gas mixtures are produced by burning combustion gases and then contain no oxygen but nitrogen and carbon dioxide. These mixtures are cheaper than, for example, pure nitrogen, which is, however, preferred. There are bottling plants that fill the empty space (head space) with inert gas before the bottle is capped in order to exclude oxidation.
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