CO2 plays an important role in bread baking process as it is one of the main gases entrapped and expanded during baking. This study first proposes a method for continuous assessment of the CO2 released from dough baked in ventilated ovens, with the application of corrections taking into account the air replacement in the oven. Assessing these quantitative data allowed further comparison with simulated data from a baking model and a refined analysis of the mechanisms underlying the CO2 release. Previous studies on CO2 release in the literatures were mainly focused on the the ability (extensibility) of dough/crumb membranes to accommodate the expansion or to resist increasing internal pressures with particular parameter of the resistance of dough membranes to rupture. In our study, the fully understanding of CO2 release mechanism were analysed. Besides the dough permeability and rigidification, total pressure should be taken into account affecting CO2 release according to Darcy Law. Experimental and simulated results obtained with artificial crust showed that the later the crust set, the longer the induction period of the CO2 release was. With expansion restricted by the crust, internal pressures increase and force the gas transport out of the bread.