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Q & A: why don't pizzas dry out?

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Most recent answer: 11/21/2014
Q:
Why when you heat a pizza above 100 degrees celsius only part of the water evaporates?
- Tom (age 28)
Paris
A:

Partly, it's just because it takes time for the water molecules to work their way out of the pizza. Even if you wait a very long time, however, the pizza will still have some water molecules. The reason is that 100° C is the temperature at which pure water boils. The water in the pizza is all bound up with other molecules. In equilibrium even above 100°C there will be many water molecules mixed in with the dough. The formal way people describe it is to say that the chemical potential of the water in the dough is lower than that of pure water at the same temperature.

Mike W.


(published on 11/21/2014)

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