Lesson 7.03 • Phase 7
Oven Spring
Rapid thermal expansion of air and alcohol in the cells up to 50°C (the dough volume skyrockets).
The spectacular moment when the volume explodes. Heat penetrates from the outside to the core. The dissolved carbon dioxide in the pores and pure alcohol (ethanol, boiling point at 78°C) evaporate! Gas expands extremely during physical heating. This physical puffing stretches the extensible gluten network (steam) to its absolute final volume maximum.
[PHASE TRANSITION & DILATATION] Oven spring is the macroscopic result of massive physical phase transitions. The rising thermal kinetics leads to the exsolution (degassing) of dissolved CO₂. At 78°C, the metabolically produced ethanol reaches its boiling point and vaporizes instantly. Meanwhile, the trapped air thermally expands according to Gay-Lussac's law. This accumulated, gigantic pneumatic internal pressure forces the still highly viscous dough matrix into a final, rapid vertical expansion.
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