Term (also chamber) for the free space with a volume of about 15 cubic centimetres in the bottle neck between the liquid surface and the closure. Depending on the type of bottling, this may actually contain air, but is often filled with inert gas or a vacuum created during bottling. In the case of sparkling wine bottles, the carbon dioxide here can expand when heated without bursting the bottles. See also under filling level.
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Diplom-Sommelier, Weinakademiker und Weinberater, Volders (Österreich)