CO2 diffusion in champagne wines: a molecular dynamics study.

Area of Science:

• Physical Chemistry
• Materials Science
• Chemical Engineering

Background:

• Diffusion is key to carbon dioxide (CO2) bubble nucleation and growth in sparkling beverages.
• The precise role of different molecules in CO2 diffusion within these complex mixtures is not fully understood.

Purpose of the Study:

• To investigate the diffusion coefficients of CO2 in water and water-ethanol mixtures simulating Champagne wine.
• To compare the accuracy of TIP5P and SPC/E water models in predicting CO2 diffusion.

Main Methods:

• Utilized force field molecular dynamics simulations for CO2 in water and water-ethanol mixtures.
• Employed generalized Fick's law to calculate multicomponent diffusion coefficients.
• Validated simulation results against experimental data for Champagne wines.

Main Results:

• CO2 diffusion coefficients were higher with the TIP5P model than the SPC/E model.
• The SPC/E model's higher propensity for hydrogen bonding influenced CO2 diffusion.
• TIP5P model simulations closely matched experimental CO2 diffusion values for Champagne (1.4-1.5 × 10⁻⁹ m²/s).

Conclusions:

• The TIP5P water model provides accurate CO2 diffusion coefficients for Champagne-like mixtures.
• CO2 diffusion in sparkling beverages is influenced by water model hydrogen-bonding characteristics.
• Diffusion coefficients in Champagne are likely stable across variations in sugar, glycerol, or peptide content.