Search

Key upgrades to a previously developed CO2-Diode Laser Sensor (CO2-DLS) were done to monitor as accurately as possible the level of gas-phase CO2 in champagne glasses. The upgraded CO2-DLS allows to access a wide range of CO2 concentrations (10-100%). An additional set of mirrors with two pairs of galvanometer scanners was developed in order to provide simultaneous measurements of gas-phase CO2 concentrations in the whole glass headspace. During the five minutes after pouring, the CO2-DLS unambiguously unveiled horizontal homogeneity in the glass headspace in terms of gas-phase CO2 concentrations. Nevertheless, a strong vertical gradient of gas-phase CO2 was highlighted, with ever increasing CO2 concentrations ranging from approximately 15% to 50% while moving away from the glass edge to the champagne interface. This strong vertical gradient was found to persist during the five next minutes following the pouring process, but with ever decreasing CO2 concentrations as time elapses.

The spectrometry is an important tool for atmospheric studies. In particular, passive spectrometric analysis implies associating a spectrometer with a heliostat. Indeed the heliostat enables to compensate for the Earth rotation relative to the Sun. In this way the sunlight can be collected at any time in order to detect atmospheric gases. Unfortunately, the instruments described in the literature need to be placed close to the spectrometer ( 5 m ) that is insufficient for the layout of our laboratory. So a servo-controlled heliostat, which is able to track the Sun with a great stability for several hours and which can be placed at a big distance from the spectrometer ( > 10 m ), has been designed and built.

Champagne and sparkling wines are multicomponent hydroalcoholic systems supersaturated with dissolved carbon dioxide (CO2). Under standard tasting conditions, CO2 progressively invades the headspace above glasses, thus progressively modifying the chemical headspace perceived by the consumer. Monitoring in situ, and as accurately as possible the level of gas-phase CO2 above liquid is therefore a challenge of importance aimed at better understanding the close relationship between the release of gas-phase CO2 and a collection of various parameters such as glass-shape, and champagne temperature, for example. The development and validation of an instrument which combines two infrared diode lasers coupled with an optical fiber and devoted to real-time monitoring of gas-phase CO2 above sparkling beverages are reported. A first set of data showing the impact of liquid phase temperature on the release of gas-phase CO2 found in the headspace of champagne glasses is presented.