Films and foams of Champagne wines

We have studied the drainage kinetics of thin films and properties of foams made from Champagne wines of three vintages and also from model hydroalcoh olic solutions of special yeast glycoproteins (YGP) with same pH, ionic str ength and almost the same ethanol concentration. It could be shown that the model solutions can remarkably mimic most film and foam properties of the wines. Aggregates were formed during the wine film drainage and showed an i mportant stabilising influence; their mobility and growth aspects in the fi lms depend on the molecular composition in wines (vintage effect), or on th e YGP concentration in solutions. The formation of aggregates could be expl ained by the film thinning, which increases the macromolecule concentration s up to their solubility limit in the films but not in the liquid bulks. Th is was interpreted in terms of displacement in the phase diagram following the increase of the macromolecule volume concentration caused by their exce ssive confinement in the film. (C) 1998 Elsevier Science Ltd. All rights re served.