What You Need to Know
When a liquid is pressurized with CO₂ (2–3 atm) at low temperature (0–5 °C), the gas dissolves and then rapidly nucleates as the valve opens, forming bubbles. Surface‑active proteins (e.g., egg white, whey) and polysaccharides (e.g., xanthan gum) adsorb to the gas–liquid interface, lowering interfacial tension and forming a viscoelastic film that retards drainage and coalescence. The balance of temperature, pressure, and surfactant concentration determines foam stability and texture.
Steps
- 1.
Espuma (Spain): Creates airy foams for modernist tapas
- 2.
Chawanmushi foam (Japan): Lightens traditional egg custard
- 3.
Foie gras mousse (France): Modern interpretation of classic pâté
The Science
Primary Reaction
CO₂ dissolution followed by rapid nucleation and stabilization of gas bubbles by surface‑active proteins/polysaccharides