title: Characterization by optical measurements of the effects of some stages of champagne technology on the adsorption layer formed at the gas/wine interface.
abstract: This study analyzes the effects of some important factors of champagne technology on the ellipticity and Brewster angle microscopy (BAM) of the air/champagne interface in view of using the optical properties of the adsorption layer of base wine to forecast the stability of the champagne bubble collar. Using standard, ultrafiltered, and ultraconcentrated wines it was observed that champagne can lose amphiphilic macromolecules which adsorb on the inner glass wall of the bottle during storage, particles such as dead yeasts can adhere to the adsorption layer, a weak increase of the ethanol content during bottle fermentation can reduce significantly the ellipticity of the adsorption layer, and CO2 has no significant effect on the properties of that layer. Surprisingly, no visible differences of the adsorption layer were noticed between the experimental champagnes of the 2004 vintage of three vine varieties (Chardonnay, Pinot noir, and Pinot meunier). From analysis of all samples it is proposed that the mean value and standard deviation of the ellipticity measured during 30 min after pouring the wine in a Petri dish are physical quantities which satisfactorily characterize the adsorption layer of champagne. When needed, further characterization of the adsorption layer may be obtained by a detailed analysis of the kinetics of ellipticity during the same period and inspection of the BAM images of the interface.
authors.affiliation: UMR 614 Fractionnement des Agro-Ressources et Emballage INRA/URCA, Centre de Recherche Environnement et Agronomique, 2 Esplanade R. Garros, F-51686 Reims.
authors.forename: K Abou
authors.initials: KA
authors.lastname: Saleh
authors.forename: V
authors.initials: V
authors.lastname: Aguié-Béghin
authors.forename: L
authors.initials: L
authors.lastname: Foulon
authors.forename: M
authors.initials: M
authors.lastname: Valade
authors.forename: R
authors.initials: R
authors.lastname: Douillard
mesh_terms: D000327:Adsorption; D002245:Carbon Dioxide / Q000737:chemistry*; D005898:Glass / Q000737:chemistry*; D055095:Optics and Photonics; D044367:Phase Transition; D014920:Wine
chemical_list: D002245:Carbon Dioxide