  The effervescence and the stability of the ring of fine bubbles crowning the
surface of a champagne glass, the "collar", constitute one of the hallmarks of
Champagne. Defects in the stability of this collar are not well understood and
account for a significant proportion of bottle return. This study aims to
better understand the surface properties of champagne wine such that the
foaming properties can be controlled more effectively. Early studies on
Champagne foaming properties using the "Mosalux" measurement of the foam level
formed by air flow in champagne through fritted glass pointed to a link between
protein concentration and foam level [5] but no satisfactory correlation
between protein content and foam stability was established. Later measurements
were conducted with either ultra-filtrates or ultra-concentrates [4]. The
authors demonstrated that macromolecule concentration was an essential
parameter in the foam stability. The stability of bubbles is usually ascribed
to the presence of an adsorption layer formed at the gas/liquid interface and
its properties [3]. Thus surface properties of Champagne were analysed by
ellipsometry and tensiometry. Measurements conducted on base wine, on
ultra-filtered base wines and degassed champagne samples showed the presence of
an adsorption layer formed at the air/champagne wine interface [6] and that
adsorption layer being composed of macromolecules in a 104 to 105 molecular
range [7]. Previous studies on champagne wine macromolecules had shown wine
macromolecules to be mostly proteins and polysaccharides [8] with very little
insight as to the chemical constitution. The present study describes the
isolation and characterization of these macromolecules and their link with the
adsorption layer.
