Name (Greek aphros = foam) for a special hollow-needle manometer for determining the concentration or pressure of carbon dioxide in liquids. The device was invented by the French chemist Edme-Jules Maumené (1818-1898) in the mid-19th century, who was conducting research in connection with the production of champagne. In viticulture, such devices are used in the production of sparkling wine and semi-sparkling wine to follow the course of a bottle fermentation, as well as for other carbonated drinks such as mineral water or lemonade.
The internal pressure in the empty space of a bottle or beverage can is recorded via a hollow needle. The prerequisite is that the closure can be pierced without loss of gas, which is most likely to be the case with a cork. The bottle or can must be shaken before measuring. The pressure is displayed in "bar" and then converted to g/l using tables or formulas, taking into account the measuring temperature (standard is 20 °Celsius) and the type of beverage. In wine or sparkling wine (sparkling wine), 1 bar corresponds to about 3 g/l, at 2 bar 4.4 g/l and at 3.5 bar about 6.5 g/l.
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Thomas Götz
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