determine temperature at which pita bread will expand in a toaster

Question

suppose you have a pita pocket of radius 5cm or .05m. We will model the pita pocket as consisting of disk with a layer of air of volume V which is contained by the surface of the bread. We will assume that no cracks or perforations exist in the pita pocket. supposing the thickness of the pocket is d = .5cm = .0025m. we can calculate the volume from the radius and thickness of the disk

$V_{pita}$ = $\pi r^2d$

suppose that the pita contains a volume of air inside

$V_{air} = \frac {V_{pita}}{5}$

and that the rest of the volume of the pita is a solid. Model the forces and pressure that cause the pita to expand. at what temperature will the air pressure inside be able to break the bonds holding the top sides of the bread together and allow it to expand under your models assumptions? rough order of magnitude estimates are fine--- but all answers should agree with experimental values of pita expansion as a function of Temperature

Answer 1

Some obscure thermal conductivity effect might heat the air inside to double the temperature, thereby doubling its pressure, but if the air expands and the pita doesn't let new gas in, it will not be able to expand more than a factor of 2 before the pressure is the same as outside. The expansion observed is a factor of a ten or more, so it's gas production.

I think that the explanation is production of steam, and the critical temperature is close to the boiling point of water, give or take the effects of solutes in water trapped in the pita. Steam production gives as much expansion as you want, and also, when I cut the pita open, I notice that it is full of steam.

(I don't think its such a terrible question either)